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 sc = new Scanner(System.in);
        int x = sc.nextInt();
        int max = 0;
        for (int i = 1; i <= x; i++) {
            for (int j = 2; j <= 10; j++) {
                int num = (int) Math.pow(i, j);
                if (num > x) {
                    break;
                }
                if (num > max) {
                    max = num;
                }
            }
        }
        System.out.println(max);
    }

}
