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 a = 1;
		
		for(int i = 2; i <= 32; i++) {
			for(int j =2; j <=10; j++) {
				double b = Math.pow(i, j);
				if(b <= X) {
					if(X - a >= X - b) {
						a = (int)b;
					}
				} else {
					break;
				}
			}
		}
		if(X < 4) {
			System.out.println(X);
		} else {
			System.out.println(a);
		}
	}
}
