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.*;
class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
         int x = Integer.parseInt(sc.next());
         int ans = 1;
         for(int i =2;i<=x;i++){
             for(int j = i*i;j<=x;j=j*i){
                 ans = Math.max(ans,j);
             }
         }
         System.out.println(ans);
    }
}