10299 - Relatives.cpp

/*
    Royal Flush , AUST
*/
#include <bits/stdc++.h>
#define pb push_back
#define INF 1<<30
#define all(x) x.begin(),x.end()
#define ms(a,v) memset(a,v,sizeof a)
#define II ({int a; scanf("%d", &a); a;})
#define LL  ({ll  a; scanf("%lld", &a); a;})
#define EPS 1e-10
#define pi acos(0.0)
using namespace std;
typedef  long long ll;
#define rep(i,n) for( __typeof(n)i = 0 ; i < n ; i++)
#define For(i,n) for( __typeof(n)i = 1 ; i <= n ; i++)
#define forstl(i,n) for(__typeof(n.begin())i = n.begin();i!=n.end();i++)
#define forab(i,a,b) for( __typeof(b) i = a ; i <= (b) ; i++ )
#define forba(i,b,a) for( __typeof(b) i = b ; i >= (a) ; i-- )

ll  phi ( ll  n ) {
	ll  i,res = n ;
	for (  i = 2 ; i * i <= n ; ++ i )
		if ( n % i == 0 ) {
			while ( n % i == 0 )
				n /= i ;
			res -= res / i ;
		}
	if ( n > 1 ) res -= res / n ;
	return res ;
}

int main(){
    ll n ;
    while(scanf("%lld",&n) && n ){
        if( n == 1 ) puts("0");
        else printf("%lld\n",phi(n));
    }
}