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 stdIn = new Scanner(System.in);

		int x = stdIn.nextInt();
		int y = 0;
		int max = Integer.MIN_VALUE;
		
		if(x==1) {
			System.out.println(1);
			return;
		}
		
		for(int i = 1; i < x; i++) {
			for(int j = 2; j < 15; j++) {
				if(Math.pow(i,j) <= x && max < Math.pow(i, j)) {
					max = (int)Math.pow(i, j);
				}
			}
		}
		System.out.println(max);
	}

}
