#include <iostream>
#include <fstream>
using namespace std;
ifstream in("gardieni.in");
ofstream out("gardieni.out");
long long v[1000001];
int main() {
	long n, t;
	in >> n >> t;
	for (long i = 0; i < n; i++) {
		long int a, b, c;
		in >> a >> b >> c;
		for (long j = a; j <= b; j++)
			if ((v[j] == 0) || (v[j] > c))
				v[j] = c;
	}
	long long s = 0;
	for (long i = 1; i <= t; i++)
		s += v[i];
	out << s;
	return 0;
}