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.io.IOException;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);

		int x = sc.nextInt();

		int result = 1;
		for(int i = 2; i <= x - 1; i++){
			int p = 2;

			while(Math.pow(i, p) <= x){
				result = (int)Math.max(result, Math.pow(i, p));
				p++;
			}
		}

		System.out.println(result);
	}
}