#include<cstdio>
using namespace std;
int main()
{
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    int n,suma=0;
    scanf("%d",&n);
    int v[n];
    for(int i=1;i<=n;i++) v[i]=i-1;
    for(int i=2;i<=n;i++)
    {
        for(int j=2*i;j<=n;j+=i)
        v[j]-=v[i];
         suma+=v[i];
    }
    printf("%d\n",2*suma+1);
}