#include <fstream>

using namespace std;

ifstream f("gardieni.in");
ofstream g("gardieni.out");

long long int price[1000005], total_price;

int main()
{
    long int n, t, i, j, a, b, c;
    f>>n>>t;
    total_price=0;
    // citesc cele n oferte, calculand costurile pe segmentele [a,b]
    for (i=1; i<=n; i++) {
        f>>a>>b>>c;
        // determin costul pe segmentul [a,b], ulterior modificand pentru a afla chiar costul minim
        for (j=a; j<=b; j++) {
                if (c<price[j] || !price[j]) price[j]=c;
        }
    }
    for (i=1; i<=t; i++) total_price+=price[i];
    g<<total_price;
    f.close();
    g.close();
    return 0;
}