#include <stdio.h>

//using namespace std;

long a[1000002],n,t;

void citire()
{
    freopen("gardieni.in","r",stdin);
    freopen("gardieni.out","w",stdout);
    scanf("%ld%ld", &n, &t);
    int i;
    for (i=1; i<=t; i++)
	a[i]=2000000000;
    long z,x,c;
    for (i=1; i<=n; i++)
    {
	scanf("%ld%ld%ld", &z, &x, &c);
	for (int j=z; j<=x; j++)
	    if (a[j]>c)
		a[j]=c;
    }
    long long s=0;
    for (i=1; i<=t; i++)
        s+=a[i];
    printf("%lld",s);
    fclose(stdin);
    fclose(stdout);
}

int main()
{
    citire();
    return 0;
}