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[]){
		int x, a, b, c;
		int n = 1;
		c = 1;
		Scanner sc = new Scanner(System.in);
		x = sc.nextInt();
		if(x == 1){
			System.out.print(1);
			return;
		}
		for(int i = 2; i <= 32; i++){
			b = i;
          	c = i;
			while(c * b <= x){
              c *= b;
			  if(n <= c){
				  n = c;
			  }
			}
		}
		System.out.print(n);
	}
}
