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();
		boolean[] expo = new boolean[X + 1];
		expo[1] = true;
		for (int i = 2; i <= X; i++) {
			int v = i * i;
			while (v <= X) {
				expo[v] = true;
				v *= i;
			}
		}
		for (int i = X; i >= 1; i--) {
			if (expo[i]) {
				System.out.println(i);
				break;
			}
		}
		sc.close();
	}
}