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 n = sc.nextInt();
		int max = 1;

		for (int i = 2; i <= Math.sqrt(n); i++) {
			int j = 2;
			int m = (int) Math.pow(i, j);
			while (m <= n) {
				m = (int) Math.pow(i, j);
				if (max < m && m <= n) max = m;
				j++;
			}
		}

		System.out.println(max);

		sc.close();
	}

}
