#include <stdio.h>
#define Tmax 1000005
#define lld long long

lld c[Tmax];
long i,n,t,A,B,C,j;
lld ctot;
const long long INF = 10000000000000000LL; // 16

int main(){
	freopen("gardieni.in","r",stdin);
   freopen("gardieni.out","w",stdout);
   scanf("%ld%ld",&n,&t);
   for(i=1;i<=t;++i) c[i]=INF;
   for(i=1;i<=n;++i){
   	scanf("%ld%ld%ld",&A,&B,&C);
      for(j=A;j<=B;++j)
        if(c[j]>C) c[j]=C;
   }

   ctot=0;
   for(i=1;i<=t;++i) ctot += c[i];
   printf("%lld\n",ctot);
   fclose(stdin); fclose(stdout);
   return 0;
}