Example

Input

3


Output

1
#include <map>
#include <set>
#include <random>
#include <vector>
#include <cassert>
#include <iostream>
#include <algorithm>
using namespace std;
mt19937 mt(12231817);
int rand_rng(int l, int r) {
	uniform_int_distribution<int> p(l, r - 1);
	return p(mt);
}
vector<int> random_distinct_integers(int l, int r, int k) {
	assert((r - l) >= k);
	set<int> s;
	for (int i = 0; i < k; i++) {
		int x = rand_rng(l, r);
		while (s.find(x) != s.end()) x = rand_rng(l, r);
		s.insert(x);
	}
	return vector<int>(s.begin(), s.end());
}
inline unsigned long long gcd(unsigned long long x, unsigned long long y) {
	while (y != 0) {
		unsigned long long r = x;
		x = y;
		y = r % y;
	}
	return x;
}
inline unsigned modpow(unsigned long long a, unsigned long long b, unsigned m) {
	unsigned ret = 1; a %= m;
	while (b) {
		if (b & 1) ret = 1ULL * ret * a % m;
		a = 1ULL * a * a % m;
		b >>= 1;
	}
	return ret;
}
std::map<unsigned long long, unsigned> prime_factorize(unsigned long long x) {
	std::map<unsigned long long, unsigned> ret;
	for (unsigned i = 2; 1ULL * i * i <= x; i++) {
		while (x % i == 0) x /= i, ret[i]++;
	}
	if (x != 1) ret[x]++;
	return ret;
}
std::vector<unsigned long long> prime_divisors(unsigned long long x) {
	std::map<unsigned long long, unsigned> res = prime_factorize(x);
	std::vector<unsigned long long> ret;
	for (std::pair<unsigned long long, unsigned> w : res) ret.push_back(w.first);
	return ret;
}
std::vector<unsigned long long> calc_divisors(unsigned long long x) {
	std::map<unsigned long long, unsigned> res = prime_factorize(x);
	std::vector<unsigned long long> ret; ret.push_back(1);
	for (std::pair<unsigned long long, unsigned> w : res) {
		int s = ret.size();
		unsigned long long mul = 1;
		for (int i = 0; i < w.second; i++) {
			mul *= w.first;
			for (int j = 0; j < s; j++) ret.push_back(ret[j] * mul);
		}
	}
	sort(ret.begin(), ret.end());
	return ret;
}
unsigned long long totient_function(unsigned long long x) {
	std::vector<unsigned long long> v = prime_divisors(x);
	unsigned long long ret = x;
	for (unsigned long long w : v) ret = ret / w * (w - 1);
	return ret;
}
int n;
int main() {
	cin >> n;
	if (gcd(n, totient_function(n)) != 1) cout << -1 << endl;
	else if (n == 2) cout << 1 << endl;
	else {
		int e = totient_function(n);
		vector<unsigned long long> v1 = calc_divisors(totient_function(e));
		int w1 = -1;
		for (int i : v1) {
			if (modpow(n, i, e) == 1) {
				w1 = i; break;
			}
		}
		vector<int> sample = random_distinct_integers(0, n, min(n, 100));
		vector<unsigned long long> v2 = calc_divisors(w1);
		int ret = -1;
		for (int i : v2) {
			bool ok = true;
			int r = modpow(n, i, e);
			for (int j : sample) {
				if (modpow(j, r, n) != j) ok = false;
			}
			if (ok) {
				ret = i; break;
			}
		}
		cout << ret << endl;
	}
	return 0;
}