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();

      int max = 1;
      
      for(int i = 2; i * i <= x; i++) {
        int num = i;
        while(num * i <= x)
          num *= i;
        max = Math.max(max, num);
      }
      System.out.println(max);
  }

}
