#include <fstream>
using namespace std;
ofstream ofis;
ifstream ifis;
 
int main(void)
{
    ofis.open("gardieni2.txt");
    ifis.open("gardieni1.txt");
    unsigned int n;
    long t,cost_total;
    long a[50005],b[50005],c[50005],minim[50005];
    ifis>>n>>t;
    for (long i=0; i<=n-1; i++)
    ifis>>a[i]>>b[i]>>c[i];
    for (int i=1; i<=t; i++)
    minim[i]=2000000000;
    for (long i=0; i<=n-1; i++)
    for (long j=a[i]; j<=b[i]; j++)
    if (c[i]<minim[j]) minim[j]=c[i];
    cost_total=0;
    for (long i=1; i<=t; i++)
    cost_total+=minim[i];
    ofis<<cost_total;
    return 0;
}