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.*;

public class Main {
  public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);

    int x = sc.nextInt();
    int tmp_p = x;
    int res = 0;

    for (int i = 0; i < x; i ++) {
      for (int j = 2; j < tmp_p; j++) {
        if ((int)Math.pow(i, j) <= x) {
          System.out.println("i=" + i + ", j=" + j);
          res = Math.max(res, (int)Math.pow(i, j));
        } else {
          tmp_p = j;
          break;
        }
      }
    }

    System.out.println(res);
  }
}