10179.cpp

#include <bits/stdc++.h>

using namespace std;

int phi(int n)
{
	int result = n;
	if (n % 2 == 0)
	{
		while (n % 2 == 0)
		{
			n /= 2;
		}
		result -= result / 2;
	}
	for (int i = 3, sq = sqrt(n); i <= sq; i += 2)
	{
		if (n % i == 0)
		{
			while (n % i == 0)
			{
				n /= i;
			}
			result -= result / i;
		}
	}
	if (n > 1)
	{
		result -= result / n;
	}
	return result;
}

int main()
{
	int n;
	while (cin >> n)
	{
		if (n == 0)
		{
			break;
		}
		cout << phi(n) << endl;
	}
	return 0;
}