#include <stdio.h>
FILE *f=fopen("gardieni.in","r"), *g=fopen("gardieni.out","w");
long long cost=0,T[1000002];
int main()
{
long j,t,n,i,a,b,c;
int p=1;
long long cost=0;
fscanf(f,"%ld %ld",&n,&t);
for (i=1;i<=n;i++)
	{
	fscanf(f,"%ld %ld %ld",&a,&b,&c);
	for (j=a;j<=b;j++)
		if ((T[j]>c) || (!T[j])) T[j]=c;
	}
for (i=1;i<=t;i++)
	cost+=T[i];
fprintf(g,"%lld\n",cost);
fclose(g);
return 0;
}