#include <fstream>
using namespace std;

ifstream f("gardieni.in");
ofstream q("gardieni.out");

int a[1000001];
long long s;
int t,n,i,j,x,b,c;

int main()
{
 f>>n>>t;
 for (i=1;i<=n;i++)
 {
     f>>x>>b>>c;
     for (j=x;j<=b;j++)
     {
        if ((a[j]==0)||(a[j]>c)){a[j]=c;}
     }
 }
     s=0;
     for (i=1;i<=t;i++){s=s+a[i];}
     q<<s;
 }