#include <bits/stdc++.h>
#define NMAX 50010
#define INF 1e9
#define TMAX 1000005
using namespace std;

ifstream fin("gardieni.in");
ofstream fout("gardieni.out");

int V[TMAX];

int main()
{
    ios :: sync_with_stdio(false);

    int n,T,x,y,c;

    fin >> n >> T;

    for(int i = 1; i <= T; i++)
        V[i] = INF;
    for(int i = 1; i <= n; i++){
        fin >> x >> y >> c;
        for(x;x <= y; x++)
            V[x] = min(V[x],c);
    }

    unsigned long long S = 0;

    for(int i = 1; i <= T; i++)
        S += V[i];

    fout << S;


    return 0;
}