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 X;

  cin >> X;

  int ans = 1;

  for(int i = 2; i < sqrt(X); ++i){
    int j = 1;
    while(j <= X){
      if(j > ans) ans=j;
      j = j * i;
    }
  }
  cout << ans << endl;

  return 0;
}
