Euler Totient Naive

/***

Bismillahir Rahmanir Rahim

 _______
|   __  \           _____
|  |__|  )_______   |   /     ____    ______
|   ____/ \__    \  |  |__   /    \  |      \
|  (        / __  \ |  __ \ /  __  \ |   /\  \
|  |       (____  / |     / \      / |__/  \  )
|__|            \/  |____/   \____/         \/

***/

#include<bits/stdc++.h>

using namespace std;

int phi(int n)
{
    int ret = n,i;

    for(i=2 ; i*i<=n ; i++)
    {
        if(n%i==0)
        {
            while(n%i==0)
            {
                n/=i;
            }

            ret-=ret/i;
        }
    }

    if(n>1)
    {
        ret-=ret/n;
    }

    return ret;
}

int main()
{

    int n;

    while(cin>>n)
    {
        cout<<phi(n)<<endl;
    }

    return 0;
}