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.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();

        int[] a = new int[1000];
        a[0] = 1;
        for (int i = 2; i < n; i++) {
            int max = i * i;
            if (max <= n) {
                do {
                    max *= i;
                } while (max <= n);
                max /= i;
                a[i-1] = max;
            }
        }

        Arrays.sort(a);
        System.out.print(a[999]);
    }
}
