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) {
		try (Scanner scanner = new Scanner(System.in)) {
			int x = scanner.nextInt(), max = 1;
			for (int i = 2; i <= (int) Math.sqrt(x); i++) {
				int pow = i * i;
				while (pow <= x) {
					max = Math.max(pow, max);
					pow *= i;
				}
			}
			System.out.println(max);
		}
	}
}
