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.*;
class Main
{
    public static void main(String[] args)
    {
        Scanner scan = new Scanner(System.in);
        int x = scan.nextInt();
        int num = 1;

        for(int i = 2; i <= 31; i++)
        {
            for(int j = 10; j > 1; j--)
            {
                double tmp = Math.pow(i, j);
                if(tmp <= x && tmp > num) num = (int) tmp;
            }
        }
        System.out.print(num);
        scan.close();
    }
}