#include<stdio.h>
#define FIN "fractii.in"
#define FOUT "fractii.out"
#define dim_m 1000001
long long a[dim_m+1],i,j,n,x;

int main()
{       
    freopen(FIN,"r",stdin);
	freopen(FOUT,"w",stdout);
	
	scanf("%lld",&n);
    
    for(i=1;i<=n;i++)       
		a[i]=i-1;
        
    for(i=2;i<=n;i++)
	 for(j=2*i;j<=n;j+=i)    
	  a[j]-=a[i];
	
	x=0;
	for(i=1;i<=n;i++) 
	 x+=a[i];
	
	printf("%lld",x*2+1);
        return 0;
}