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) throws Exception {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();
		sc.close();

		for (int i = x; i > 0; i--) {
			for (int b = 1; b < 32; b++) {
				for (int p = 2; p < 10; p++) {
					if ((int) Math.pow(b, p) == i) {
						System.out.println(i);
						return;
					}
				}
			}
		}
	}
}
