#include<stdio.h>
long n,c;
long minim[1000010];

void read()
{
	freopen("gardieni.in","r",stdin);
	freopen("gardieni.out","w",stdout);
	scanf("%ld%ld",&n,&c);
	long i;
	for(i=1;i<=c;i++)
		minim[i]=999999999;
	long a,b,x,j;
	for(i=1;i<=n;i++)
	{
		scanf("%ld%ld%ld",&a,&b,&x);
		for(j=a;j<=b;j++)
			if(minim[j]>x)
				minim[j]=x;
	}
	long long s=0;
	for(i=1;i<=c;i++)
		s=s+minim[i];
	printf("%lld\n",s);
}

int main()
{
	read();
	return 0;
}