10179.cpp

/**
 *                                   ____
 *       ____ ___  ____ ________  __/ __/
 *      / __ `__ \/ __ `/ ___/ / / / /_
 *     / / / / / / /_/ / /  / /_/ / __/
 *    /_/ /_/ /_/\__,_/_/   \__,_/_/
 *
 *    @link : https://the-redback.com
 */
#include <bits/stdc++.h>
using namespace std;
#define inf       HUGE_VAL
#define mem(a, b) memset(a, b, sizeof(a))

int phi(int n) {
    int res = n;
    int i;
    for (i = 2; i * i <= n; i++) {
        if (!(n % i)) res -= res / i;
        while (!(n % i)) n /= i;
        if (n == 1) break;
    }
    if (n > 1) res -= res / n;
    return res;
}

int main() {
    int tc, t = 1;
    int i, j, k, l, x;
    // scanf("%d",&tc);
    while (~scanf("%d", &k)) {
        if (k == 0) return 0;
        k = phi(k);
        printf("%d\n", k);
    }
    return 0;
}