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.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;

class Main{
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int x = Integer.parseInt(br.readLine());
        int ans = 1;
        for(int i = 2; i <= Math.sqrt(x); i++){
            int can = i;
            while(can*i <= x){
                can *= i;
            }
            ans = Math.max(ans,can);
        }
        System.out.println(ans);
    }
}