#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
int n,t;
struct str{int a,b,c;} A[50006];
void citire()
{
	ifstream fin ("gardieni.in");
	fin >>n>>t;
	for (int i=1;i<=n;i++)
		fin>>A[i].a>>A[i].b>>A[i].c;
	fin.close();
}
int main ()
{
	int s=0;
	ofstream fout("gardieni.out");
	citire();
	for (int i=1;i<n;i++)
		for (int j=i+1;j<=n;j++)
			if (A[i].c>A[j].c)
			{
				A[n+1]=A[i];
				A[i]=A[j];
				A[j]=A[n+1];
			}
	for (int i=1;i<=t;i++)
		for (int j=1;j<=n;j++)
			if (i>=A[j].a && i<=A[j].b)
			{
				s+=A[j].c;
				break ;
			}
	/*for (int i=1;i<=n;i++)
		fout << A[i].a<<A[i].b<<A[i].c<<endl;*/
	fout<<s;
	return 0;
}