#include <stdio.h>
#include <stdlib.h>
#include <iostream.h>
struct firme{
	int a;
	int b;
	int c;
};

FILE *fin=fopen("gardieni.in","r"),
	 *fout=fopen("gardieni.out","w");
int main(){
	int minim[1000],i,j,cost,t,n;
	firme v[505];
	fscanf(fin,"%d %d",&n,&t);
	for(i=1; i<=n; i++) fscanf(fin,"%d %d %d",&v[i].a,&v[i].b,&v[i].c);
	for(i=1; i<=t; i++) minim[i]=32767;
	for(i=1; i<=n; i++)
		for(j=v[i].a; j<=v[i].b; j++)
			if(v[i].c<minim[j]) minim[j]=v[i].c;
	cost=0;
	for(i=1; i<=t; i++)
		cost=cost+minim[i];
	fprintf(fout,"%d\n",cost);
	fclose(fin);
	fclose(fout);
	return 0;
}