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 N = sc.nextInt();
    
    if (N == 1) { 
      System.out.println(1); return; 
    }
    
    int max = Integer.MIN_VALUE;
    for (int i = 2; i <= N; i++) {
      for (int j = 2; j <= N; j++ ){
        double pow = Math.pow((double)i, (double)j);
        if (pow > N) {
          break;
        }
        max = Math.max((int)pow, max);
      }
    }
    System.out.println(max);
  }
}
      