#include<iostream>
#include<string>
#include<stdlib.h>
#include<fstream>
#include <time.h> 
#include <algorithm>

using namespace std;

int main()
{
    ifstream in("gardieni.in");
    ofstream of("gardieni.out");
	int n,t,i,min,a[100][100],suma=0;
	in>>n>>t;
	
	for(i=1;i<=n;i++)
	{	in>>a[i][1]>>a[i][2]>>a[i][3];
	}
	int count=0;
	while(count<t)
	{
		count++;
		min=10000;
		for(i=1;i<=n;i++)
			if(a[i][1]<=count && a[i][2]>=count && a[i][3]<min)
				min=a[i][3];	
		suma=suma+min;			
	}
	of<<suma;
	
	in.close();
	of.close();
}