#include <cstdio>
#include <string>

const char FIN[] = "gardieni.in", FOU[] = "gardieni.out";
const int MAX = 1000005;

int V[MAX];
int N, T;
int A, B, C;

int main()
{
    freopen (FIN , "r" , stdin);
    freopen (FOU , "w" , stdout);

    scanf("%d %d", &N, &T);

    memset ( V, -1, sizeof (int) * ( T + 1 ) );

    for (int i = 1 ; i <= N ; ++i)
    {
        scanf("%d %d %d", &A, &B, &C);

        for (int j = A ; j <= B ; ++j)
            if ( V[j] > C || V[j] == -1 ) V[j] = C;
    }

    long long sol = 0;

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

    printf("%lld", sol);

    return 0;
}