#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<climits>
#include<cmath>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<numeric>
#include<functional>
#include<algorithm>
#include<bitset>
#include<tuple>
#include<unordered_set>
#include<unordered_map>
#include<random>
#include<array>
#include<cassert>
using namespace std;
#define INF ((1<<30)-1)
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()



bool is_square(long long x) {
	long long s = sqrt(x) + 0.1;
	return s * s == x;
}


int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);

	long long n;
	cin >> n;
	if (n <= 2) {
		cout << 2 << endl;
		return 0;
	}


	for (long long p = 2; p*p*p <= n*100 ; p++) {
		long long rem = n % p;
		long long m = n;
		bool ok = true;
		while (m) {
			if (m % p != rem) {
				ok = false;
				break;
			}
			m /= p;
		}
		if (ok) {
			cout << p << endl;
			return 0;
		}
	}

	for (int d = 9; d >= 1; d--) {
		if (n % d == 0 && 2 <= n / d - 1 && d < n / d - 1) {
			cout << n / d - 1 << endl;
			return 0;
		}
	}

	cout << 2 << endl;

 	return 0;
}