#include <stdio.h>

long long sum;
long i, n, t, j, a, b, c, T[1000100];

int main()
{
	freopen ("gardieni.in", "rt", stdin);
	freopen ("gardieni.out", "wt", stdout);

	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 (T[j] > c || T[j] == 0)
				T[j] = c;
	}

	for (i = 1; i <= t; i ++)
		sum += T[i];

	printf("%lld\n", sum);

	return 0;
}