#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define rng(a) a.begin(),a.end()
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<P> vp;
#define dame { puts("-1"); return 0;}
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

vector<pair<ll, int>> fac;
void PrimeFactorInit(ll x){
    if(x >= 2){
        for(ll i = 2; i <= x; i++){
            if(i * i > x)break;
            if(x % i == 0){
                int cnt = 0;
                while(x % i == 0){
                    cnt++;
                    x /= i;
                }
                pair<ll, int> p;
                p.first = i;
                p.second = cnt;
                fac.push_back(p);
            }
        }
        if(x > 1){
            pair<ll, int> p;
            p.first = x;
            p.second = 1;
            fac.push_back(p);
        }
    }
}

int main() {
    ll n;
    cin >> n;
    PrimeFactorInit(n);
    rep(i, fac.size()){
        if(fac[i].first > 2){
            ll ans = fac[i].first;
            if(n % (ll)4 == (ll)0 && (ll)4 < ans)ans = 4;
            cout << ans << endl;
            return 0;
        }
    }
    cout << min(n, (ll)4) << endl;
    return 0;
}