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();

    sc.close();

    int max = 1;

    for (int i = 1; i < X; i++) {

      for (int j = 2; j < X; j++) {
        double k = Math.pow(i, j);
        if ((int)k <= X) {
          max = Math.max(max, (int)k);
        } else {
          break;
        }
      }

    }
    
    System.out.println(max);
    
  }

}