#include <bits/stdc++.h>
#define ll long long
using namespace std;
ll n,b,br,suma,skor,r,br2,br6,suma6,suma2,skor2,spenalty2,minskor=2e18,minskor2=2e18,br3,suma3,skor3,skor4,skor5,minskor4=2e18,suma4,br4,spenalty4,minim,minko,br8,suma8,spenalty8,brp,skor8,spenalty,br5,suma5,skor6,skor7,suma7,br7;
vector<ll>rupe[1000005],rupke[25],perm,perma,ruponi[25],permo,rupaa[25],rupicice[1000005],rupcage[1000005],rupasi[1000005],rup[600005];
struct slog{
	ll h,p,index;
	bool ubacen;
}stix[1000005];
void unos(){
    scanf("%lld",&n);
    scanf("%lld",&b);
    for(ll i=1;i<=n;i++)
        scanf("%lld",&stix[i].h);
    for(ll i=1;i<=n;i++){
        scanf("%lld",&stix[i].p);
        stix[i].index=i;
        stix[i].ubacen=0;
    }//unos gotov

  }


  bool cmp(slog a, slog b){
      if(a.h!=b.h) return a.h<b.h;
      return a.p>b.p;
  }
  bool cmp2(slog a,slog b){return a.index<b.index;}
  void obradatela(){
    sort(stix+1,stix+n+1,cmp);
     r=n;
     br=1;
    for(ll i=1;i<=n;i++){


        if(!stix[i].ubacen){
            stix[i].ubacen=true;
            rupe[br].push_back(stix[i].index);
            suma+=stix[i].h;
            if(suma>b){

                if(!stix[r].ubacen){
                        rupe[br].pop_back();
                    rupe[br].push_back(stix[r].index);
                    spenalty+=stix[r].p;
                    stix[r].ubacen=true;
                    stix[i].ubacen=false;
                    r--;
                    suma=0;
                    br++;
                   i-=2;
                }
            }


        }
        else if(suma==b){
            suma=0;
            br++;
        }

    }
    if(suma==0)
        br--;
    skor=br*br*br+spenalty;
  }
  void alg2(){
    sort(stix+1,stix+n+1,cmp);
    do{
			br2=1;
        for(ll i=1;i<=n;i++){
            rupke[br2].push_back(stix[i].index);
            suma2+=stix[i].h;
            if(suma2>=b){
                br2++;
                suma2=0;
                spenalty2+=stix[i].p;
            }
        }
        if(suma2==0)br2--;
        if(rupke[br2].size()>0)br2++;
        skor2=br2*br2*br2+spenalty2;
        if(skor2<minskor){
            perm.clear();
            minskor=skor2;
            perm.push_back(br2);
            for(ll i=1;i<=br2;i++){
				perm.push_back(rupke[i].size());

                for(ll j=0;j<rupke[i].size();j++){
                    perm.push_back(rupke[i][j]);
                }
            }

        }

        for(ll i=1;i<=br2;i++)rupke[i].clear();

        suma2=0;
        spenalty2=0;
        skor2=0;
    }while(next_permutation(stix+1,stix+n+1,cmp2));}
void teloobrada(){
    for(ll i=1;i<=n;i++)stix[i].ubacen=false;
    br5=1;
    sort(stix+1,stix+n+1,cmp);
    for(ll i=1;i<=n;i++){
        if(!stix[i].ubacen){
            stix[i].ubacen=true;
            rupicice[br5].push_back(stix[i].index);
            suma5+=stix[i].h;
            if(suma5+stix[i+1].h>b){suma5=0;br5++;}
        }
    }
    if(suma5==0)br5--;
    skor5=br5*br5*br5;
}
void obraditotelo(){
    for(ll i=1;i<=n;i++)stix[i].ubacen=false;
    sort(stix+1,stix+n+1,cmp2);
    br6=1;
    for(ll i=1;i<=n;i++){
        if(!stix[i].ubacen){
            stix[i].ubacen=true;
            rupcage[br6].push_back(stix[i].index);
            suma6+=stix[i].h;
            if(suma6+stix[i+1].h>b){suma6=0;br6++;}
        }



    }
     if(suma6==0)br6--;
    skor6=br6*br6*br6;



}

  void alg4(){
      sort(stix+1,stix+n+1,cmp);
    do{
            br4=1;
            for(ll i=1;i<=n;i++)stix[i].ubacen=0;
            int q=n;
        for(ll i=1;i<=n;i++){
                if(!stix[i].ubacen){
                    rupaa[br4].push_back(stix[i].index);
                    suma4+=stix[i].h;
                    stix[i].ubacen=true;

                    if(suma4>=b){
                            if(!stix[q].ubacen){
                        stix[i].ubacen=false;
                        rupaa[br4].pop_back();
                        stix[q].ubacen=true;
                        rupaa[br4].push_back(stix[q].index);
                        suma4=0;
                        spenalty4+=stix[q].p;
                        br4++;
                        q--;
                        i-=2;
                            }

                    }

                }


        }
        if(suma4==0)br4--;
        skor4=br4*br4*br4+spenalty4;
        if(skor4<minskor4){
            minskor4=skor4;
            permo.clear();
            permo.push_back(br4);
            for(ll i=1;i<=br4;i++){
                permo.push_back(rupaa[i].size());
                for(ll j=0;j<rupaa[i].size();j++)
                    permo.push_back(rupaa[i][j]);
            }
        }
         for(ll i=1;i<=br4;i++)rupaa[i].clear();
        suma4=0;
        spenalty4=0;
        skor4=0;
    }while(next_permutation(stix+1,stix+n+1,cmp2));






  }
void permoispis(){
    printf("%lld\n",permo[0]);
    for(ll i=1;i<permo.size();i+=permo[i]+1){
        printf("%lld ",permo[i]);
        for(ll j=1;j<=permo[i];j++){
            printf("%lld ",permo[i+j]);
        }
        printf("\n");
    }
    printf("\n");



}
void dobaraleta(){
    sort(stix+1,stix+n+1,cmp);
    for(int i=1;i<=n;i++)stix[i].ubacen=false;
    br7=1;
    int y=n;
    for(int i=1;i<=n;i++){
        if(!stix[y].ubacen){
            stix[y].ubacen=true;
            rupasi[br7].push_back(stix[y].index);
            suma7+=stix[y].h;}
            if(suma7+stix[i].h>b ){
                    suma7=0;br7++;
                    y--;
            }
            else if(suma7+stix[i].h<=b){
                rupasi[br7].push_back(stix[i].index);
                stix[i].ubacen=true;
                suma7+=stix[i].h;
            }

        }
if(suma7==0)br7--;

    skor7=br7*br7*br7;









}
void alg3(){
		sort(stix+1,stix+n+1,cmp2);
    do{

			br3=1;
        for(ll i=1;i<=n;i++){


            	ruponi[br3].push_back(stix[i].index);
            	suma3+=stix[i].h;

            	if((suma3+stix[i+1].h)>b){suma3=0;br3++;}


        }
        if(suma3==0)br3--;

        skor3=br3*br3*br3;
        if(skor3<minskor2){
            perma.clear();
            minskor2=skor3;
            perma.push_back(br3);
            for(ll i=1;i<=br3;i++){
				perma.push_back(ruponi[i].size());

                for(ll j=0;j<ruponi[i].size();j++){
                    perma.push_back(ruponi[i][j]);
                }
            }

        }



        for(ll i=1;i<=br3;i++)ruponi[i].clear();

        suma3=0;

        skor3=0;
    }while(next_permutation(stix+1,stix+n+1,cmp2));
}
void nekispis(){
    printf("%lld\n",br7);
    for(int i=1;i<=br7;i++){
        printf("%lld ",rupasi[i].size());
        for(int j=0;j<rupasi[i].size();j++)
            printf("%lld ",rupasi[i][j]);
        printf("\n");
         }
    printf("\n");


}
void permispis(){
    printf("%lld\n",perm[0]);
    for(ll i=1;i<perm.size();i+=perm[i]+1){
        printf("%lld ",perm[i]);
        for(ll j=1;j<=perm[i];j++){
            printf("%lld ",perm[i+j]);
        }
        printf("\n");
    }
    printf("\n");
  }
void permaispis(){

	 printf("%lld\n",perma[0]);
		for(ll i=1;i<perma.size();i+=perma[i]+1){
			printf("%lld ",perma[i]);
			for(ll j=1;j<=perma[i];j++){
				printf("%lld ",perma[i+j]);
			}
			printf("\n");}


}

bool cmp3(slog a,slog b){return a.h>b.h;}
void npolarupa(){
    for(int i=1;i<=n;i++)stix[i].ubacen=false;
    ll a=1;
    sort(stix+1,stix+n+1,cmp);
    for(int i=1;i<=n;i++){
       if(i<=(n/2+n%2)){
            if(!stix[i].ubacen){
                stix[i].ubacen=true;
                rup[i].push_back(stix[i].index);
                suma8+=stix[i].h;
                if(suma8>b){suma8=0;spenalty8+=stix[i].p;}
            }
       }
       if((i==n/2+n%2) && (brp==0)){
            sort(stix+1,stix+n+1,cmp3);
            brp++;
            i=1;
       }
    }

br8=n/2+n%2;
//cout<<br8;
skor8=br8*br8*br8+spenalty8;
}
void npolaispis(){
    printf("%lld\n",br8);
    for(int i=1;i<=br8;i++){
        printf("%lld ",rup[i].size());
        for(int j=0;j<rup[i].size();j++)
            printf("%lld ",rup[i][j]);
        printf("\n");
    }
    printf("\n");




}

  void ispis(){
  printf("%lld\n",br);
	for(ll i=1;i<=br;i++){
		printf("%lld ",rupe[i].size());
		for(ll j=0;j<rupe[i].size();j++)
			printf("%lld ",rupe[i][j]);
		printf("\n");}
		printf("\n");}
void obradispis(){
    printf("%lld\n",br5);
    for(ll i=1;i<=br5;i++){
        printf("%lld ",rupicice[i].size());
        for(ll j=0;j<rupicice[i].size();j++){
            printf("%lld ",rupicice[i][j]);
        }
        printf("\n");
    }
    printf("\n");



}
void obradjenispis(){
    printf("%lld\n",br6);
    for(ll i=1;i<=br6;i++){
        printf("%lld ",rupcage[i].size());
        for(ll j=0;j<rupcage[i].size();j++)
            printf("%lld ",rupcage[i][j]);
        printf("\n");
    }
    printf("\n");

}
int main(){
    freopen("sticks.in","r",stdin);
	freopen("sticks.out","w",stdout);
unos();
if(n<=12){
     alg4();
    alg2();
	alg3();
//    cout<<"2 : "<<minskor<<endl<<"3 : "<<minskor2<<endl<<"4 : "<<minskor4<<endl;

	minim=min(minskor,min(minskor2,minskor4));
//	cout<<"Minim: "<<minim<<endl;
	if(minim==minskor)permispis();
	else if(minim==minskor2)
    permaispis();
	else permoispis();
}
else{
    obradatela();
    teloobrada();
    obraditotelo();
    dobaraleta();
    npolarupa();
//    cout<<"Br7: "<<br7<<endl;
//    cout<<"Obradatela: "<<skor<<endl<<"Telo Obrada: "<<skor5<<endl<<"Obradi to telo: "<<skor6<<endl<<"Ovaj novi: "<<skor7<<endl<<"N pola: "<<skor8<<endl;
    minko=min(skor,min(skor5,min(skor6,min(skor7,skor8))));
//    cout<<"Minko: "<<minko<<endl;
//    npolaispis();
//    cout<<"br8: "<<br8<<endl<<spenalty8;
//    cout<<endl<<endl<<endl;
    if(minko==skor)ispis();
    else if(minko==skor5)obradispis();
    else if(minko==skor6)  obradjenispis();
    else if(minko==skor7)nekispis();
    else npolaispis();
}

return 0;
}