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 k = 1;
    int max = 1;

    for (int i = 1; i < x; i++) {
      for (int j = 2; j < x; j++) {
        k = (int)Math.pow(i,j);
        if (k <= x) {
          max = Math.max(max,k);
        }
      }
    }

    System.out.println(max);

  }

}
