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;
import java.util.TreeSet;
 
public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();
		
		TreeSet<Integer> expo = new TreeSet<>();
		expo.add(1);
		for(int i = 1; i <= x; i++) {
			for(int n = 2; n < x; n++) {
				double result = Math.pow((double)i,(double)n);
				if(result > x) {
					break;
				}else {
					expo.add((int)result);
				}
			}
		}
		
		System.out.println(expo.last());
	}
}