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) {
        //99999は門番
        int[] check = {1,4,8,9,16,25,27,32,36,49,64,81,100,121,125,128,144,169,196,216,225,243,256,289,324,343,361,400,441,484,512,529,576,625,676,729,784,841,900,961,1000,99999};

        Scanner sc = new Scanner(System.in);
        int max  = sc.nextInt();

        for (int i = 0; i < check.length; i++) {
            if(max < check[i]){
                System.out.println(check[i - 1]);
                return;
            }
        }
    }

}
