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.Scanner;


public class Main {
	
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        
        long X = sc.nextLong();
        long max = 1;
        
        for(long i=2;i*i<=X;i++){
        	
        	long pow = i*i;
        	
        	for(;pow<=X;pow *= i)
        		if(max<pow)
        			max = pow;
        	
        }
        
        System.out.println(max);
		
	}


		

    
}