#include<fstream>
#define dim 50007
#define timpu 1<<19

using namespace std;

ifstream f("gardieni.in");
ofstream g("gardieni.out");
long long w[dim];
long t,n;
inline long long min(long long a,long long  b){
	if(a<b)
		return a;
	return b;
}
long long s;
int main (){
	f>>n>>t;
	long a,b,c;
	for(long i=1;i<=t;++i)
		w[i]=timpu;
	
	for(long i=1;i<=n;i++){
		f>>a>>b>>c;
		for(long j=a;j<=b;j++)
			w[j]=min(w[j],c);
	}
	for(long i=1;i<=t;i++)
		s+=w[i];
	g<<s<<"\n";
	return 0;
}