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.*;

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

		Scanner sc = new Scanner(System.in);

		int X = sc.nextInt();
		
		int max=1;
		for(int t=2;t<=(int)Math.sqrt(X);t++){
			int s=1;
			while((int)Math.pow(t,s) <= X){
				s++;
			}
			if(max < (int)Math.pow(t,s-1)) max = (int)Math.pow(t,s-1);
		}

		System.out.println(max);
		
	}
}