#include<cstdio>
using namespace std;
int N,T,minim[1000010];
long long sol;

inline int Min(int a,int b)
{
	if(a<b)
		return a;
	return b;
}

int main()
{
	int i,j,a,b,c;
	freopen("gardieni.in","r",stdin);
	scanf("%d %d",&N,&T);
	for(i=1;i<=T;i++)
		minim[i]=2000000000;
	for(i=1;i<=N;i++)
	{
		scanf("%d %d %d",&a,&b,&c);
		for(j=a;j<=b;j++)
			minim[j]=Min(minim[j],c);
	}
	for(i=1;i<=T;i++)
		sol+=minim[i];
	freopen("gardieni.out","w",stdout);
	printf("%lld\n",sol);
	return 0;
}