#include <iostream>
#include <algorithm>

using namespace std;

int N;

int main()
{
	cin >> N;
	
	if (N <= 10)
	{
		long long result = 1;
		for (int i = 1; i <= N - 1; ++i)
			result = result * i % N;
		cout << result << '\n';
	}
	else
	{
		bool prime = true;
		for (int i = 2; i * i <= N && prime; ++i)
			if (N % i == 0)
				prime = false;
		
		if (!prime)
			cout << 0 << '\n';
		else
			cout << N - 1 << '\n';
	}
}