#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll pcnt=0;
ll n;
ll phi(ll n)
{
ll ans=n;
for (ll a=2;a*a<=n;a++)
if (n%a==0)
{
	ans = ans / a * (a-1);
	while (n%a ==0)
	n=n/a;
}
    if (n!=1) ans=ans/n*(n-1);
	return ans;
     }
int main(){
	cin>>n;
	ll ans=0;
	ll i=1;
	for(;i*i<=n;i++){
	if(n%i==0) ans+=i*phi(n/i)+(n/i)*phi(i);
	if(i*i==n) ans+=i*phi(i);
	} 
	cout<<ans;
	return 0;
}