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: Wrong Answer)

import java.util.*;
import java.io.*;
 
public class Main{
    public static void main(String[] args){
        Main m = new Main();
        m.input();
    }
 
    public void input(){
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int ans = 0;
        for(int i = 1; i <= 32; i++){
            if(i * i <= a){
                ans = i;
            }else{
                break;
            }
        }
        sc.close();
        System.out.println(ans * ans);
    }
    
}