You are given a positive integer X. Find the largest perfect power that is at most X. Here, a perfect power is an integer that can be represented as b^p, where b is an integer not less than 1 and p is an integer not less than 2.

Constraints

* 1 ≤ X ≤ 1000
* X is an integer.

Input

Input is given from Standard Input in the following format:


X


Output

Print the largest perfect power that is at most X.

Examples

Input

10


Output

9


Input

1


Output

1


Input

999


Output

961
#include <bits/stdc++.h>
using namespace std;

int main() {
  int N;
  cin >> N;
  int mx = 1;
  for (int i = 2; i * i <= N; i++) {
    for (int j = 0; pow(i, j) <= N; j++) {
      mx = max(mx, (int) pow(i, j));
    }
  }
  cout << mx << "\n";
}