#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;
using P = pair<int, int>;
constexpr ld EPS = 1e-12;
constexpr int INF = numeric_limits<int>::max() / 2;
constexpr int MOD = 1e9 + 7;

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

    ll N;
    cin >> N;
    set<ll> st;
    for (ll i = 3; i * i <= N; i++)
    {
        if (N % i == 0)
        {
            st.insert(i);
            st.insert(N / i);
        }
    }
    st.insert(N);
    cout << (*st.begin()) << endl;
}