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;
public class Main{
    public static void main(String args[]){
        Scanner scan=new Scanner(System.in);
        int X=scan.nextInt();
        int max=1;
        int i,j;
        for(i=2;i<=Math.sqrt(X);i++){
            j=i;
            while(j*i<=X){
                j*=i;
            }
            if(max<j){
                max=j;
            }
        }
        System.out.println(max);

    }
}