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);
		int x = sc.nextInt();

		int max = 0;
		if(x == 1) {
			max = 1;
		} else if(x == 2) {
			max = 2;
		} else {
			int maxnum = (int)Math.sqrt(x);
			for(int i = 2; i <= maxnum; i++) {
				int tmp = i;
				while(true) {
					tmp =  tmp * i;
					if(tmp > x) {
						max = Math.max(max, tmp/i);
						break;
					}
				}
			}
		}
		System.out.println(max);
	}
}
