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 = sc.nextInt();
    boolean[] rui = new boolean[x + 1];
    rui[1] = true;
    for(int b = 2; b <= x; b++) {
      int s = (b * b);
      while(s <= x) {
        rui[s] = true;
        s *= b;
      }
    }
    int ans = 1;
    for(int i = x; i >= 1; i--) {
      if(rui[i]) {
        ans = i;
        break;
      }
    }
    System.out.println(ans);
  }
}
