#include<stdio.h>
long long sol[1000001],cost,a,b,c,N,T;
int main()
{ freopen("gardieni.in","r",stdin);
  freopen("gardieni.out","w",stdout);
  long long i,j;
  scanf("%lld %lld",&N,&T);
  for(i=1;i<=N;i++)
     { scanf("%lld %lld %lld",&a,&b,&c);
       for(j=a;j<=b;j++)
	  if(sol[j]==0 || sol[j]>c) sol[j]=c;
     }
  for(i=1;i<=T;i++) cost+=sol[i];
  printf("%lld\n",cost);
  return 0;
}