#include<cstdio>
using namespace std;
int v[1000001];
int main()
{
    freopen("gardieni.in","r",stdin);freopen("gardieni.out","w",stdout);
    long long s=0;int a,b,c,i,n,t;
	scanf("%d%d",&n,&t);
	for(i=1;i<=n;++i)
	{
		scanf("%d%d%d",&a,&b,&c);
		for(;a<=b;++a)
			if(!v[a]||c<v[a])
				v[a]=c;
	}
	for(i=1;i<=t;i++)
		s+=v[i];
	printf("%lld",s);
}