#include <cstdio>
using namespace std;
long cost[1000005],n,a,b,c,t;
long long s=0;
int main()
{
    freopen("gardieni.in","r",stdin);
    freopen("gardieni.out","w",stdout);
    scanf("%lld %lld",&n,&t);
    for(long long i=1;i<=n;i++)
    {
        scanf("%lld %lld %lld",&a,&b,&c);
        for(long long j=a;j<=b;j++)
        {
            if(cost[j]>c || cost[j]==0) cost[j]=c;
        }
    }
    for(long i=1;i<=t;i++) s+=cost[i];
    printf("%lld",s);
    return 0;
}