#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <numeric>
#include <utility>
#include <tuple>

#define rep(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<ll, ll>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
template<typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template<typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); }
template<typename T> bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; }
template<typename T> void print(T a) { cout << a << '\n'; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
struct input {
    int n;
    input() : n(0) {}
    input(int _n) : n(_n) {}
    template<typename T> operator T() const && { T val; cin >> val; return move(val); }
    template<typename T> operator vector<T>() const && { vector<T> val(n); for (T &e: val) { cin >> e; } return move(val); }
};
// clang-format on

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    ll n = input();
    ll ans = n;
    for (ll i = 2; i * i <= n; i++) {
        if (n % i == 0) {
            if (i != 2) {
                chmin(ans, i);
            }
            if (n / i != 2) {
                chmin(ans, n / i);
            }
        }
    }
    print(ans);
    return 0;
}