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.Scanner;

class Main {
  public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);

    double num;

    num = sc.nextInt();

    double temporaryNum = 1;
    if (num < 4) {
      System.out.println(1);
      return;
    }

    for (int i = 2; Math.pow(i, 2) <= num; i++) {
      for (int n = 2; Math.pow(i, n) <= num; n++) {
         if (temporaryNum < Math.pow(i, n)) {
           temporaryNum = Math.pow(i, n);
         }
      }
    }
    System.out.println((int)temporaryNum);
    return;
  }
}
