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;

class Main{
	public static void main(String[] args) {
		Scanner stdIn=new Scanner(System.in);
		int x=stdIn.nextInt(),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);
	}
}