#include <stdio.h>

using namespace std;

int a[1000002],n,t;

void citire()
{
    freopen("gardieni.in","r",stdin);
    freopen("gardieni.out","w",stdout);
    scanf("%d%d", &n, &t);
    for (int i=1; i<=n; i++)
        a[i]=2000000000;
    int z,x,c;
    for (int i=1; i<=n; i++)
    {
        scanf("%d%d%d", &z, &x, &c);
        for (int j=z; j<=x; j++)
            if (a[i]>c)
                a[i]=c;
    }
    long long s=0;
    for (int i=1; i<=t; i++)
        s+=a[i];
    printf("%lld",s);
    fclose(stdin);
    fclose(stdout);
}

int main()
{
    citire();
    return 0;
}