#include <iostream>
#include <fstream>
#define nmax 1000005

using namespace std;

const char iname[] = "gardieni.in";
const char oname[] = "gardieni.out";

ifstream fin(iname);
ofstream fout(oname);

int ap[nmax];
long long i, j, st, dr, cost, T, N, sum;

int main()
{
	fin >> N >> T;
	for(i = 1; i <= N; i ++)
	{
		fin >> st >> dr >> cost;
		for(j = st; j <= dr; j ++)
		{
			if(ap[j] == 0)
				ap[j] = cost;
			if(cost < ap[j])
				ap[j] = cost;
		}
	}
	for(i = 1; i <= T; i ++)
		sum = sum + ap[i];
	fout << sum;
	return 0;
}