#include <stdio.h>
#include <stdlib.h>

struct interval
{
	int a,b,c;
};

int n,t;
interval v[50005];
int v2[1000005];

int comp(const void *a, const void *b)
{
	interval *aa=(interval*) a, *bb=(interval*) b;
	interval x=*aa, y=*bb;
	return x.c-y.c;
}

int main()
{
	int i,j,x,y,c;
	long long sol;
	
	FILE *in  = fopen("gardieni.in","r");
	FILE *out = fopen("gardieni.out","w");
	
	fscanf(in,"%d%d",&n,&t);
	for (i=0; i<=t+1; i++)
		v2[i]=2500000;
	for (i=0; i<n; i++)
	{
		fscanf(in,"%d%d%d",&x,&y,&c);
		for (j=x; j<=y; j++)
			if (v2[j]>c)
				v2[j]=c;		
	}
	
	sol=0;
	for (i=1; i<=t; i++)
		sol+=v2[i];
	fprintf(out,"%lld\n",sol);
	
	fclose(in);
	fclose(out);
	
	return 0;
}