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: Accepted)

import java.util.Scanner;

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

		int x = sc.nextInt();
		int ans = 1;

		for (int b = 1; b <= x; b++) {
			for (int p = 2; p < 1000; p++) {
				int pow = (int)Math.pow(b, p);
				if (pow <= x)
					if (ans < pow) ans = pow;
			}
		}
		System.out.println(ans);
	}
}