//欧拉函数#include<cstdio>#include<cstring>#include<cstdlib>#include<iostream>#include<algorithm>#include<cmath>#include<queue>using namespace std;int ef(int n){    int cnt = n;    for(int i=2;i<=n;i++)    {        if(n%i==0)        {            cnt-=cnt / i;            n/=i;            while(n%i==0)            {                n/=i;            }        }    }    return cnt;}int main(){int n;    scanf("%d",&n);    cout<<ef(n)<<endl;    return 0;}