#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    ll N; cin >> N;
    ll ans = N - 1;
    // 1 <= d < p
    // dddddd = d(111111) = d(1+p+p^2+p^3+p^4+p^5)
    // N = d * (p^(keta) - 1) / (p - 1)
    vector<ll> div;
    for(ll i = 1; i * i <= N; i++) {
        if(N % i == 0) {
            div.push_back(i);
            if(i * i != N) div.push_back(N / i);
        }
    }
    
    for(ll d : div) {
        ll k = N / d;
        // (p^x - 1) / (p - 1) = N / d = k
        // p^x - 1 = kp - k
        // p(k - p^(x-1)) = k - 1

        for(ll p = 2; p * p <= k - 1; p++) {
            if((k - 1) % p == 0) {
                // k - p^(x-1) = (k - 1) / p = y
                ll y = (k - 1) / p;
                // p^(x-1) = k - y = z
                ll z = k - y;
                while(z % p == 0) z /= p;
                if(z == 1) {
                    ans = min(ans, p);
                }
            }
        }
    }
    cout << ans << endl;
}