#include<stdio.h>

#define Nmax 1000001

int main() {
	freopen("fractii.in","r",stdin);
	freopen("fractii.out","w",stdout);
 
	int v[Nmax],n,i,j;
	long long sol=0;
 
	scanf("%d",&n);
	for(i=1; i<=n; i++) v[i]=i-1;
 
	for(i=1; i<=n; i++) {
		for(j=2*i; j<=n; j+=i) 
			v[j]=v[j]-v[i];
		sol+=(long long)v[i];
	}
	
	printf("%lld",sol*2+1);
	
	return 0;
}