#include<stdio.h>
#define N 50006
#define T 1000001
int n,t,x[N],y[N],c[N],min[T],sum;
void read()
{
	int i;
	scanf("%d%d",&n,&t);
	for(i=1;i<=n;i++)
		scanf("%d%d%d",&x[i],&y[i],&c[i]);
}
void solve()
{
	int i,j;
	for(i=1;i<=t;i++)
		min[i]=T;
	for(i=1;i<=n;i++)
		for(j=x[i];j<=y[i];j++)
			if(c[i]<min[j])
				min[j]=c[i];
	sum=0;
	for(i=1;i<=t;i++)
		sum+=min[i];
	printf("%d\n",sum);
}
int main()
{
	freopen("gardieni.in","r",stdin);
	freopen("gardieni.out","w",stdout);
	read();
	solve();
	return 0;
}