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 <iostream>
#include <cmath>
using namespace std;

int main()
{
  int X;
  cin >> X;

  int ans = 1;
  for(int i = 2; i < X; ++i) {
    for(int j = 2; pow(i, j) <= X; ++j) {
      ans = max(ans, int(pow(i, j)));
    }
  }

  cout << ans << endl;
}
