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 s = new Scanner(System.in);
		int num = s.nextInt();
		int ans = 1;

		for (int a = 2; a < 32; a++) {

			for (int b = 2; b < 9; b++) {
				if ((int) Math.pow(a, b) <=num) {
					ans = Math.max(ans, (int) Math.pow(a, b));
				}
			}
		}
		System.out.println(ans);

	}
}
