#include<cstdio>
#define Tmax 1000005

FILE *f=fopen("gardieni.in","r");
FILE *g=fopen("gardieni.out","w");

using namespace std;

int n,k,v[Tmax],timp,s;
int main()
{
	int left,right,cost;
	int i;
	fscanf(f,"%d%d",&n,&timp);
	for(i=1;i<=n;i++)
	{
		fscanf(f,"%d%d%d",&left,&right,&cost);
		for(;left<=right;left++)
			if(v[left]==0||cost<v[left])
				v[left]=cost;
	}
	for(i=1;i<=timp;i++)
		s+=v[i];
	fprintf(g,"%d",s);
	fclose(f);
	fclose(g);
	return 0;
}