#include<stdio.h>
int min[1000000];
int main () {
	long long a,b,c,s=0,i,j,n,t;
	freopen("gardieni.in","r",stdin);
	freopen("gardieni.out","w",stdout);
	scanf("%lld%lld",&n,&t);
	for(i=0;i<t;++i)
		min[i]=10000000;
	for(i=0;i<n;++i){
		scanf("%lld%lld%lld",&a,&b,&c);
		for(j=a-1;j<b;++j)
			if(c<min[j])
				min[j]=c;
	}
	for(i=0;i<t;++i)
		s+=min[i];
	printf("%lld\n",s);
	return 0;
}