#include <fstream>
std::ifstream f1("gardieni.in");
std::ofstream f2("gardieni.out");
int main()
{
	unsigned int cost[1000000], n;
	unsigned long long s, u, t, a, b, j, i, c;
	f1>>n>>t;
	for (i=0; i<n; i++)
	{
		f1>>a>>b>>c;
		for (j=a; j<=b; j++)
			if ((cost[j]==0)||(cost[j]>c))
				cost[j]=c;
	}//for i
	for (i=1; i<=t; i++)
	{
		//f2<<cost[i]<<" ";
		u=cost[i];
		s+=u;
	}//for i
	f2<<s;
	f1.close();
	f2.close();
	return 0;
}//main