#include <cstdio>

const int MAX_SIZE(1000001);

int cost [MAX_SIZE];

int main (void)
{
	std::freopen("gardieni.in","r",stdin);
	std::freopen("gardieni.out","w",stdout);
	int n, t, a, b, c, index;
	std::scanf("%d %d",&n,&t);
	while (n)
	{
		std::scanf("%d %d %d",&a,&b,&c);
		for (index = a ; index <= b ; ++index)
			if (!cost[index] || cost[index] > c)
				cost[index] = c;
		--n;
	}
	long long sum(0);
	for (index = 1 ; index <= t ; ++index)
		sum += cost[index];
	std::printf("%lld\n",sum);
	std::fclose(stdin);
	std::fclose(stdout);
	return 0;
}