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.ArrayList;
import java.util.Collections;
import java.util.Scanner;
public class Main {
    public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    int x = sc.nextInt();
    ArrayList<Integer>ans  = new ArrayList<>();
    
    for(int i=1; i<=x; i++) {
    	for(int j=2; j<=1000; j++) {
    		if(x >= (int)Math.pow(i, j)) {
    			ans.add((int)Math.pow(i, j));
    	}
    }
    }
    Collections.sort(ans,Collections.reverseOrder());
    			System.out.println(ans.get(0));
    	}
}