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 N = sc.nextInt();
    int M = 0;
    int ans = 0;
    
    if(N<4){
        ans = 1;
    }else{
    for(int i=2; i<=N; i++){
        M = 0;
        for(int j=2; M<=N; j++){
                        if(ans < M){
                ans = M;
            }
            M = (int)Math.pow(i,j);

        }
    }  
    }
    System.out.println(ans);
    }
}