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.*;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();
		sc.close();
		int max = 0;
		for (int i = 1; i <= 1000; ++i) {
			if (i != 1) {
				for (int j = 2; j <= 10; ++j) {
					int tmp = (int) Math.pow(i, j);
					if (tmp <= x)
						max = Math.max(max, tmp);
					else
						break;
				}
			} else {
				if (i <= x)
					max = Math.max(max, i);
			}
		}
		System.out.println(max);
	}

}
