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 stdIn = new Scanner(System.in);
		int x = stdIn.nextInt();
        int a = 0, b, p, i, t;
		for(b = 1;b <= x;b++) {
			t = b;
			for(p = 2;p <= x;p++) {
				t *= b;
				if(t <=x && a < t) a = t;
			}
		}
		if(x == 1) a = 1;
		System.out.print(a);
	}
}
