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.Scanner;

class Main {
    public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       int x = sc.nextInt();
       double t = 1, ans = 1;
       sc.close();
       
       for(int i=1; i<x; i++) {
           for(int j=2; t<x && i>1; j++) {
              t = Math.pow(i, j); 
              if (t<=x) ans = t;
           }
           t = 0;
           if(ans == x) break;
       }

       System.out.println((int)ans);

    }
}