#include<cstdio>

using namespace std;

long long a[1000001],n,s;

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