#include<stdio.h>
long long x[1000005],i,j,n,m,k,l,a,b,c,s;
int main()
{
	freopen("gardieni.in","r",stdin);
	freopen("gardieni.out","w",stdout);
	scanf("%lld%lld",&n,&k);
	for (i=1;i<=n;i++)
	{
		scanf("%lld%lld%lld",&a,&b,&c);
		for (j=a;j<=b;j++)
			if (x[j]>c||x[j]==0) x[j]=c;
	}
	for (j=1;j<=k;j++)
	s+=x[j];
	printf("%lld\n",s);
	return 0;
}