#include <stdio.h>       
long long n,i,j,a[1000000];       
int main()       
{       
freopen("fractii.in","rt",stdin);
freopen("fractii.out","wt",stdout);       
scanf("lld",&n);;       
for (i=1; i<=n; i++) a[i]=i-1;       
for (i=2; i<=n; i++)       
for (j=i*2; j<=n; j+=i) a[j]-=a[i];       
for (i=0, j=0; i<=n; j+=a[i]) ++i;   
printf("%lld",j*2+1);       
return 0;       
}