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.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        List<Integer> list = new ArrayList<Integer>();
        list.add(1);
        for (int i = 100; i >= 2; i--) {
            int tmp = i * i;
            while (tmp <= n) {
                list.add(tmp);
                tmp *= i;
            }
        }
        list.sort(Comparator.reverseOrder());
        System.out.println(list.get(0));
    }
}
