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;
public class Main {

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

		int x = stdIn.nextInt();
		int y = 0;
		int max = Integer.MIN_VALUE;
		
		if(x==1) {
			System.out.println(1);
			return;
		}
		
		for(int i = 1; i < x; i++) {
			for(int j = 2; j < 15; j++) {
				if(Math.pow(i,j) <= x && max < Math.pow(i, j)) {
					max = (int)Math.pow(i, j);
				}
			}
		}
		System.out.println(max);
	}

}