#include <stdio.h>
#define Nmax 1000001
using namespace std;

long long nr_ire;
int red[Nmax],n;

int main()
{
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    scanf("%d",&n);

    for(int i=1;i<=n;i++)red[i]=i-1;
    for(int i=2;i<=n;i++)
    {
        for(int j=i*2;j<=n;j=j+i)
            red[j]=red[j]-red[i];

        nr_ire=nr_ire+red[i];
    }

    printf("%lld",nr_ire*2+1);

}