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 pow;
        int ans=1;
        for(int i=2;i<=Math.sqrt(x);i++){
            pow=1;
            while(Math.pow(i, ++pow)<=x){
                ans=Math.max(ans,(int)Math.pow(i, pow));
            }
        }
        System.out.println(ans);
        

    }
}