#include <cstdio>

using namespace std;

int v[1000005];

int main()
{
    freopen("gardieni.in","r",stdin);
    freopen("gardieni.out","w",stdout);

    int n,t,i,a,b,cost;
    long long sum=0;

    scanf("%d%d",&n,&t);

    for(i=1;i<=n;i++)
    {
        scanf("%d%d%d",&a,&b,&cost);
        for(int j=a;j<=b;j++)
        {
            if(v[j]==0 or v[j]>cost) v[j]=cost;
        }
    }

    for(i=1;i<=t;i++) sum+=v[i];

    printf("%d ",sum);



    return 0;
}