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();

		for(int i=X;i>0;i--) {

			if(i == 1) {
				System.out.println(1);
				return;
			}

			for(int b=(int)Math.sqrt(i)+1;b>2;b--) {
				int temp = i;
				int p = 0;
				while(temp % b == 0) {
					p++;
					temp /= b;
				}

				if(temp == 1 && p > 1) {
					System.out.println(i);
					return;
				}
			}
		}
	}
}
