#include <fstream>

#define lint long long int
using namespace std;

const int NMAX = 50005;
const int TMAX = 1000005;

int best[TMAX];

int main()
{
    ifstream cin("gardieni.in");
    ofstream cout("gardieni.out");

    int n = 0, t = 0;
    cin >> n >> t;

    int a, b, c;
    while (n --) {
        cin >> a >> b >> c;

        while (a <= b) {
            if (!best[a] || c < best[a])
                best[a] = c;
            ++ a;
        }
    }

    lint ans = 0;
    for (int i = 1; i <= t; ++ i)
        ans += best[i];

    cout << ans << '\n';

    cin.close();
    cout.close();
    return 0;
}