# include <iostream>
# include <cstdio>
# include <queue>
# include <vector>
# include <stack>
# include <map>
# include <cmath>
# include <algorithm>
# include <stdio.h>
#include <cstdio>
#include <ctime>
#include <random>
#include <utility>
using namespace std;
mt19937 randGenerator(28564789);//27081999
int n,m,b;
int a[1005][1005];
int tek[1005];
bool isit[1005];
bool otg[1005];
long long maxsum=0;
 clock_t start;
int news[1005];
bool newsit[1005];
void proveri()
{
    int sum = 0;
    int i,j;
    for(i=1;i<=m;i++)
    {
        sum = sum + (news[i]%b)*(news[i]%b);
    }
    if(sum<=maxsum)return ;
    for(i=1;i<=m;i++)
    {
        tek[i]=news[i];
        isit[i]=newsit[i];
    }
    maxsum = sum;
    return ;
}
 void tryit()
 {
     double time;
time = 4.8;
if(n>500)time = 3.90;
int i,j;
long long p=0;
while((clock() - start ) / (double) CLOCKS_PER_SEC<=time)
{
    p = (randGenerator())%n;
    p = p+ 1;
    if(newsit[p]==1)
    {
        for(i=1;i<=m;i++)
            news[i]-=a[p][i];
    }
    else
        for(i=1;i<=m;i++)
            news[i]+=a[p][i];
    newsit[p] = 1 - newsit[p];
    proveri();

}
return ;
 }
void backtrack(int v)
{
   // cout<<v<<endl;
    int i,j;
    long long sum=0;
    if(v>n)
    {
        for(i=1;i<=m;i++)
            sum+=(tek[i]%b)*(tek[i]%b);
           // cout<<sum<<endl;
        if(maxsum<sum)
        {
            maxsum=sum;
            for(i=1;i<=n;i++)
                otg[i]=isit[i];
        }
        return ;
    }
    isit[v]=0;
    backtrack(v+1);
    isit[v]=1;
    for(i=1;i<=m;i++)
    {
        tek[i]+=a[v][i];
        //tek[i]=tek[i]%b;
    }
    backtrack(v+1);
   isit[v]=0;
    for(i=1;i<=m;i++)
    {
        tek[i]-=a[v][i];
        //tek[i]=tek[i]%b;
    }
    return ;
}
void solve1()
{
    int i,j;

backtrack(1);
int br=0;
long long sum1=0;
for(i=1;i<=n;i++)
  {
      br+=otg[i];
     // sum1+=otg[i]*
  }
cout<<br<<endl;
for(i=1;i<=n;i++)
{
    if(otg[i]==1)
        cout<<i<<endl;
}
}
void add(int v)
{
    long long sum=0,i;
    for(i=1;i<=m;i++)
    {
        tek[i]+=a[v][i];
      //  sum = sum + (tek[i]%b)*(tek[i]%b);
    }
    isit[v]=1;
   // if(sum>maxsum){maxsum=sum;return ;}
    //for(i=1;i<=m;i++)
   //     tek[i]-=a[v][i];
    return ;

}
void add1(int v)
{
    long long sum=0,i;
    for(i=1;i<=m;i++)
    {
        tek[i]+=a[v][i];
        sum = sum + (tek[i]%b)*(tek[i]%b);
    }

    if(sum>maxsum){maxsum=sum;  isit[v]=1;return ;}
    for(i=1;i<=m;i++)
        tek[i]-=a[v][i];
    return ;

}
void del(int v)
{
     long long sum=0,i;
    for(i=1;i<=m;i++)
    {
        tek[i]-=a[v][i];
       // sum = sum + (tek[i]%b)*(tek[i]%b);
    }isit[v]=0;
   // if(sum>maxsum){maxsum=sum;return ;}
   // for(i=1;i<=m;i++)
    //    tek[i]+=a[v][i];
    return ;
}
void del1(int v)
{
     long long sum=0,i;
    for(i=1;i<=m;i++)
    {
        tek[i]-=a[v][i];
        sum = sum + (tek[i]%b)*(tek[i]%b);
    }
    if(sum>maxsum){maxsum=sum;isit[v]=0;return ;}
    for(i=1;i<=m;i++)
        tek[i]+=a[v][i];
    return ;
}
bool check()
{
    int i;
    long long sum=0;
    for(i=1;i<=m;i++)
        sum+=(tek[i]%b)*(tek[i]%b);
    if(sum>maxsum){maxsum=sum;return 1;}
    else
        return 0;
}
int main()
{
   // cout<<randGenerator()<<endl;
     ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    freopen ("subsetselection.out","w",stdout);
    freopen ("subsetselection.in","r",stdin);
cin>>n>>m>>b;
int i,j;
double time;
time = 0.50;
if(n>500)time = 3.0;
for(i=1;i<=n;i++)
    for(j=1;j<=m;j++)
  {
       cin>>a[i][j];
       a[i][j]=a[i][j]%b;
  }
if(n<=20&&m<=20){solve1();return 0;}

    double duration;

    start = clock();
    if(n==1000){
            bool fl=1;
//while((clock() - start ) / (double) CLOCKS_PER_SEC<=time)
for(i=1;i<=n;i++)
{
    if(!fl)break;
    for(j=i+1;j<=n;j++){
            if((clock() - start ) / (double) CLOCKS_PER_SEC>=time){fl=0;break;}
    if(isit[i]==0)
    {
    add(i);
    }
    else
        del(i);

     if(isit[j]==0)
    {
    add(j);
    }
    else
        del(j);
        if(!check())
        {
            if(isit[i]==0)
    {
    add(i);
    }
    else
        del(i);

         if(isit[j]==0)
    {
    add(j);
    }
    else
        del(j);
        }
}
}}
else
{
    while((clock() - start ) / (double) CLOCKS_PER_SEC<=time)
for(i=1;i<=n;i++)
{
    for(j=i+1;j<=n;j++)
        {
    if(isit[i]==0)
    {
    add(i);
    }
    else
        del(i);

     if(isit[j]==0)
    {
    add(j);
    }
    else
        del(j);
        if(!check())
        {
            if(isit[i]==0)
    {
    add(i);
    }
    else
        del(i);

         if(isit[j]==0)
    {
    add(j);
    }
    else
        del(j);
        }
}
}
}
tryit();
int br=0;
long long sum1=0;
for(i=1;i<=n;i++)
  {
      br+=isit[i];
     // sum1+=otg[i]*
  }
cout<<br<<endl;
for(i=1;i<=n;i++)
{
    if(isit[i]==1)
        cout<<i<<endl;
}
return 0;
}