#include <stdio.h>

long int v[1000000], n, a, b, c, cost, t;

int main()
{
	freopen("gardieni.in","r",stdin);
	freopen("gardieni.out","w",stdout);

	long i, j;
	scanf("%ld %ld",&n, &t);
	for (i = 1; i <= n; i++)
	{
		scanf("%ld %ld %ld", &a, &b, &c);
		for (j = a; j <= b; j++) if (!v[j] || v[j] > c) v[j] = c;
	}

	for (i = 1; i <= t; i++) cost += v[i];
	printf("%ld\n",cost);
	return 0;
}