// #pragma GCC optimize ("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target ("avx,avx2,fma")
#include <bits/stdc++.h>

using std::cin, std::cout, std::cerr;
using ll = long long;

int main() {
    std::ios::sync_with_stdio(false);
    ll n; cin >> n;
    ll ans = n;
    auto upd = [&](ll x) {
        if(x > 2)
            ans = std::min(ans, x);
    };
    for(ll d = 1; d * d <= n; d ++) if(n % d == 0) {
        upd(d);
        upd(n / d);
    }
    cout << ans << '\n';
}