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 ans = 1;
    for(int i = 2; i < 50; i++) {
      for(int j = 2; j < 10; j++) {
        if((int)Math.pow(i, j) <= x) ans = Math.max(ans, (int)Math.pow(i, j));
      }
    }
    System.out.println(ans);
  }
}