#include <cstdio>
using namespace std;

int n,m,vagon,vagdin,maxvagon,pleas;

struct vag{
  int mt;
  int x;
  int y;
};

vag vg[300];


void read(){
  scanf ("%d%d", &n, &m);
  for ( int i = 0; i < m; i++ ){
      scanf ("%d%d%d", &vg[i].mt,&vg[i].x,&vg[i].y );
  }
}


void solve(){

  for ( int i = 0; i < n; i++ ){
    for ( int j = 0; j < m; j++ ){
      if(vg[j].x==i+1) pleas+=vg[j].mt;
      if(vg[j].y==i+1) pleas-=vg[j].mt;

    }
      vagon=pleas/64;
      if(pleas%64!=0)vagon++;
     //  printf ( "%d\n",pleas);
	if(maxvagon<vagon)maxvagon=vagon;
	//printf ( "%d\n",maxvagon);
      }
 return;
}
int main(){
  freopen ( "bdz.in", "r", stdin );
  freopen ( "bdz.out", "w", stdout );
  read();
  solve();
 printf ( "%d\n",maxvagon);
}