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();
		int tmp=1;
		for(int i=1;i<X;i++) {
			for(int j=2;j<=100;j++) {
				if(Math.pow(i, j)>tmp&&Math.pow(i, j)<=X) {
 
					tmp = (int) Math.pow(i, j);
								}
				if(Math.pow(i, j)>X) {
						break;
				}
 
			}
 
		}
		System.out.println(tmp);
	}
 
}