#include <cstdio>
#include <cmath>
const int N = 1e9;
int isnp[50005],p[50005],pcnt;

inline void getPrime(const int n = sqrt(N)) {
	isnp[0]= isnp[1]=1;
	for (register int i=2; i<=n; ++i) {
		if (!isnp[i]) p[pcnt++]=i;
		for (register int j=0; i*p[j]<=n && j<pcnt; ++j) {
			isnp[i*p[j]]=1;
			if (!(i% p[j])) break ;
		}
	}
}

int main() {
	getPrime();	int n;
	while (scanf(" %d", &n) && n) {
		int _sqrt = sqrt(n),ans= n;
		for (register int j = 0; p[j]<=_sqrt && j<pcnt; ++j) {
			if (n % p[j]==0) {
				while (n % p[j]==0)n/=p[j];
				ans = 1ll * ans *(p[j]-1)/ p[j];
			}
		}
		if (n!=1) ans = 1ll* ans * (n-1)/n;
		printf("%d\n", ans);
	}
	return 0;
}