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();
		int ans = 0;
		
		for(int b=1; b <= X; b++) {
			for(int p = 2; p <= 1000; p++) {
				if(Math.pow(b,p) <= X) {
					ans = (Math.max((int)Math.pow(b,  p), ans));
					}
				}
		
		}
		
		System.out.println(ans);
		

	}
}
