#include <stdio.h>
#define inf 2000000000

long n,t,i,j,x,y,z,a[1000002];
long long suma;

int main(){
    freopen("gardieni.in","r",stdin);
    freopen("gardieni.out","w",stdout);
    
    scanf("%ld %ld",&n,&t);
    for (i=1;i<=t;i++)a[i]=inf;
    
    for (i=1;i<=n;i++){
        scanf("%ld %ld %ld",&x,&y,&z);
        for (j=x;j<=y;j++)if (z<a[j])a[j]=z;
    }
    
    for (i=1;i<=t;i++)suma=(long long)suma+a[i];
    
    printf("%lld\n",suma);
    
    return 0;
    
}