#include <stdio.h>
#define prim(x) (ciur[x]==0)
#define N 1000000
int ciur[N+1],n;
int main()
{
	freopen("fractii.in","r",stdin);
	freopen("fractii.out","w",stdout);
	scanf("%d",&n);
	fclose(stdin);
	int i,j,t,s=0;
	for(i=2;i<=n;++i)
	{
		if(prim(i))
		{
			t=n/i;
			for(j=i;j<=n;j+=i)
			{
				if(ciur[j]==0) ciur[j]=t;
				else ciur[j]=ciur[j]+t-n/j;
			}
		}
		s+=ciur[i];
	}
	int solutie=n*n-s;
	printf("%d\n",solutie);
	fclose(stdout);
	return 0;
}