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 Java7 (OpenJDK 1.7.0) (judge verdict: Wrong Answer)

import java.util.*;
class Main{

     public static void main(String []args){
        Scanner scan = new Scanner(System.in);
       
        int n =scan.nextInt();
        int count = 0;
        for(int i = n ; i >=1 ; i--){
            if(Math.sqrt(i) - (int)Math.sqrt(i)==0){
                System.out.println(i);
                break ;
            }          
        }
      
     }
}