#include <bits/stdc++.h> using namespace std; double n, l, r; int main() { cin >> n; l = -100.00; r = 100.00; while (r - l > 1e-8) { double mid = (l + r) / 2; if (mid * mid * mid >= n) { r = mid; } else { l = mid; } } cout << fixed << setprecision(6) << l << endl; return 0; }