Problem:
Score : 200 points

Problem Statement

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.

Sample Input 1

10

Sample Output 1

9

There are four perfect powers that are at most 10: 1, 4, 8 and 9.
We should print the largest among them, 9.

Sample Input 2

1

Sample Output 2

1

Sample Input 3

999

Sample Output 3

961

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.util.*;


public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int x = sc.nextInt();
ArrayList<Integer> list = new ArrayList<Integer>();
ArrayList<Integer> plist = new ArrayList<Integer>();
for(int i=2;i<32;i++){
  boolean judge=true;
  int count=2;
  while(judge){
    if((int)Math.pow(i,count)<x){
      list.add((int)Math.pow(i,count));
      count++;
    }else{
      judge=false;
    }
  }
}

        System.out.print(plist.get(list.size()-1));

  }
}