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
import java.util.*;
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int X = sc.nextInt();
    for(int i=X;i>0;i--){
      if(isRui(i)){
        System.out.println(i);
        return;
      }
    }
  }
  
  public static boolean isRui(int n){
     boolean res = false;
    for(int i=1;i<=n;i++){
      for(int j=2;j<12;j++){
        if(Math.pow(i,j)==n){
          return true;
        }
      }
    }
    return res;
  }
  
}