#include <cstdio>

using namespace std;

int n;

long long ans;

int v[1000100];

int main() {
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    scanf("%d",&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];
        ans+=v[i];
    }
    printf("%lld",2*ans+1);
}