#include <cstdio>
#include <vector>
#include <set>

using namespace std;

#define MAXT 1000005
#define MAXN 50015

int N, T;
int Min[MAXT];

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

	scanf("%d %d", &N, &T);
	memset( Min, 0x3f, sizeof(Min) );
	for (int i = 1; i <= N; i++)
	{
		int L, R, Cst;
		scanf("%d %d %d", &L, &R, &Cst);
		for (int k = L; k <= R; k++)
			if (Cst < Min[k])
				Min[k] = Cst;
	}

	long long S = 0;
	for (int i = 1; i <= T; i++)
		S += Min[i];
	printf("%lld\n", S);

	return 0;
}