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();
    
    if(x>=1 && x<=1000){
      if (x == 1) {
        System.out.println(1);
        return;
      }
      int max = 1;
      for(int i = 2; i <= x; i++){
        for(int k = 2; Math.pow(i,k) <=x; k++){
          max = Math.max(max,(int)Math.pow(i,k));
         }
      }
        
        System.out.println(max);
      
    }else{
      System.out.println("入力条件が誤っています");
    } 
  }  
}