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) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		sc.close();
		int[] Array = new int[1000];
		Arrays.fill(Array,0);
		int max = 1;
		if(X <= 3) {
			System.out.println(1);
		}
		else {
			for (int i = 2; i <= X; i++) {
				int num = i * i;
				while (num <= X) {
					max = Math.max(max, num);
					num *= i;
				}
			}
			System.out.println(max);
		}	
	}
}