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){
Scanner sc = new Scanner(System.in);
int x=Integer.parseInt(sc.next());
double temp=0;
for(int i=1;i<32;i++){
for(int j=2;j<10;j++){
    if(Math.pow(i,j)<=x){
        
temp=Math.max(temp,Math.pow(i,j));
        }
        }
}
int ans=(int)temp;
System.out.println(ans);
}
}