#include <iostream>
using namespace std;
typedef long long ll;
ll powaa(int a) {
    ll n = 1;
    for (int i = 1; i <= a; i++) n *= a;
    return n;
}
int main() {
    int b;
    ios::sync_with_stdio(false);
    cin >> b;
    for (int i = 1; i <= b; i++)
        if (powaa(i) == b) {
            cout << i;
            break;
        }
    cout << -1;
}

可能各位感觉会有点抽象 $:-)$