#include <bits/stdc++.h>

using namespace std;

int main() {
    long long n;
    cin >> n;
    long long ans = n;
    for (long long i = 2; i * i <= n; i++) {
        if (n % i == 0) {
            if (i != 2) {
                ans = min(ans, i);
            }
            ans = min(ans, n / i);
        }
    }
    cout << ans << endl;
    return 0;
}