#include <fstream.h>

ifstream fin("gardieni.in");
ofstream fout("gardieni.out");

struct sirul{
    int a,b,c;
};

typedef struct sirul sip;
sip sir[50010];
int minim[1000010];
long S,n,t;

void citire()
{
   fin>>n>>t;
     for (int i=0;i<n;i++)
	fin>>sir[i].a>>sir[i].b>>sir[i].c;
   fin.close();
}
void suma()
{
   for (int k=0;k<t;k++)
      minim[k]=123542133;

   for (int j=0;j<n;j++)
     for (int y=sir[j].a ; y<=sir[j].b ; y++)
	if (sir[j].c<minim[y])
	   minim[y]=sir[j].c;

	   for (int pp=0;pp<t;pp++)
	       S+=minim[pp];
}

int main()
{
   citire();
   suma();
   fout<<S<<"\n";
   fout.close();
   return 0;
}