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.*;
import java.lang.*;

class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int x = sc.nextInt();
    int MAX_ROOT = (int)Math.sqrt(x);
    double e = 1;
    double max = e;
    for(int i = 2;i <= MAX_ROOT;i++){
      for(int j = 1;j <= 9;j++){
        e = Math.pow(i,j);
        if(e > x) break;
        if(max < e){
          max = e;
        }
      }
    }
    int emax = (int)max;
    System.out.println(emax);
  }
}