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 ans = 0;
		
		for (int i = 1; i < 33; i++){
			
			int tmp = i;
			
			for (int j = 0; j < 9; j++){
				tmp *= i;
				
				if (ans < tmp && tmp <= X){
					ans = tmp;
			}
			
			}

		}
		
		System.out.println(ans);

	}
}