#include<fstream>
using namespace std;
ifstream in("gardieni.in");
ofstream out("gardieni.out");
int N,T,v[1000009];

int main()
{

    int i,a,b,c,j;
    in>>N>>T;
    for(i = 1 ; i <= T ; i++)
        v[i] = 1500000;
    for(i = 1 ; i <= N ; i++)
    {
        in>>a>>b>>c;
        for( j = a ; j <= b && j <= T; j++)
            v[j] = min(v[j],c);
    }
    long long cost = 0;
    for(i = 1 ; i <= T ; i++)
        cost+=v[i];
    out<<cost;
    return 0;
}