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 X = sc.nextInt();
		double a = Math.sqrt(X);
		long max=1;
		for(int b =2;b<=X;b++) {
			for(int q =2;Math.pow(b, q)<=X;q++) {
					max=Math.max((int)Math.pow(b, q),max);
			}
		}
		System.out.println(max);
		sc.close();
	}
}
