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++){
    int cnt = i;
    while(cnt <= n){
      cnt *= i;
    }
    ans = max(ans, cnt/i);
  }
  cout << ans << endl;
}