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

public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    int x = Integer.parseInt(in.readLine());
    int max = 0;
    for(int i=2; i<=x; i++) {
      for(int j=2; Math.pow(i,j)<=x; j++) {
          max = Math.max((int)Math.pow(i,j),max);
      }
    }
    System.out.println(x==1?1:max);
  }
}