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.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int input = sc.nextInt();
		int nums[] = { 8, 27, 64, 125, 216, 343, 512, 729, 32, 243, 128, 512 };
		for (int i = 1; i <= 32; i++) {
			if (input == i * i) {
				System.out.println(i * i);
				break;
			}
			if ((input > i * i) && input < (i + 1) * (i + 1)) {
				int binary = i * i;
				for (int s : nums) {
					if (s < input && s > binary) {
						System.out.println(s);
						break;
					}
					System.out.println(binary);
					break;
				}
			}
		}
	}
}