#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

#include<cmath>

#define ll long long

using namespace std;

const int N=1e5+;

ll ans,n;

ll phi(ll a)

{

    ll ret=a;

    for(ll i=;i*i<=a;i++)

        if(a%i==)

        {

            ret=ret/i*(i-);

            while(a%i==)a/=i;

        }

    if(a>)ret=ret/a*(a-);

    return ret;

}

int main()

{

    scanf("%lld",&n);

    for(ll i=;i*i<=n;i++)

        if(n%i==)

            if(i!=n/i)ans+=i*phi(n/i)+(n/i)*phi(i);

            else ans+=i*phi(n/i);

    printf("%lld\n",ans);

    return ;

}