#include<iostream>

#include<cstring>

#include<cstdio>

#include<algorithm>

#include<cmath>

using namespace std;

const int N=+;

int p,tot;

int vis[N],prime[N],phi[N];

void get_phi()

{

    phi[]=;

    for (int i=;i<=N;i++)

    {

        if (!vis[i])

        {

            prime[++tot]=i;

            phi[i]=i-;

        }

        for (int j=;j<=tot&&prime[j]*i<=N;j++)

        {

            vis[prime[j]*i]=;

            if (i%prime[j]==)

            {

                phi[i*prime[j]]=phi[i]*prime[j];

                break;

            }

            else phi[i*prime[j]]=phi[i]*(prime[j]-);

        }

    }

}

int main()

{

    get_phi();

    while (scanf("%d",&p)!=EOF)

    {

        printf("%d\n",phi[p-]);

    }

    return ;

}