#include<fstream.h>
#include<math.h>
int main()
{
	long n,catid=1,o=1;
	ifstream In("fractii.in");
	ofstream Out("fractii.out");
	In>>n;
	for(long k=2;k<=n;k++)
	{
		for(int g=2;g<=sqrt(k);g++)
		{
			if(k%g==0||(k%(k%g)==0)){catid++;}
		}
		o=o+((k-catid)*2);catid=1;
	}
	if(n%10==0){o=o-n;}
	Out<<o;
	Out.close();In.close();
	return 0;
}