#include<fstream>
#include<algorithm>
using namespace std;

int n, t, tmp[1000001];
long long sum;
int main()
{
	ifstream fin("gardieni.in");
	ofstream fout("gardieni.out");
	fin >> n >> t;
	
	int a, b, c;
	for (int i = 1; i <= n; ++i)
	{
		fin >> a >> b >> c;
		for (int j = a; j <= b; ++j)
			if (tmp[j] > c || tmp[j] == 0)
				tmp[j] = c;
	}
	for (int i = 1; i <= t; ++i)
		sum += tmp[i];
	
	fout << sum;
}