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 ans = 1;

  for (int i = 2; i * i <= N; i++) {
    for (int j = i * i; j <= N; j *= i) {
      ans = max(ans, j);
    }
  }

  cout << ans << endl;
}