#include <stdio.h>

#define MAX_T 1000005
#define FIN "gardieni.in"
#define FOUT "gardieni.out"
#define min(a, b) ((a) < (b) ? (a) : (b))
#define INF 0x3f3f3f3f

int N, T, A[MAX_T];
long long Res;

int main(void)
{
    int i, j, k;

    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);

    scanf("%d %d", &N, &T);
    for (i = 1; i <= T; ++i) A[i] = INF;
    for (; N; --N)
    {
        scanf("%d %d %d", &i, &j, &k);
        for (; i <= j; ++i) A[i] = min(A[i], k);
    }
    for (i = 1; i <= T; ++i)
        Res += A[i];
    printf("%lld\n", Res);

    return 0;
}