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;

class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);

		int x = sc.nextInt();
		int ans = 1;

		for (int b = 1; b <= x; b++) {
			for (int p = 2; p < 1000; p++) {
				int pow = (int)Math.pow(b, p);
				if (pow <= x)
					if (ans < pow) ans = pow;
			}
		}
		System.out.println(ans);
	}
}