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) {
        Scanner sc = new Scanner(System.in);
        
        int X = sc.nextInt();
        int answer =1;
        
        for(int i=2; i*i<=X; i++){
            int max =i*i;
            while(max<=X){
            if(max >= answer){
                answer = max;
            }
                max *= i;
            }
        }
        
        System.out.println(answer);
        
    }
}
