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.Scanner;


public class Main {
	
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        
        long X = sc.nextLong();
        long max = 1;
        
        for(long i=2;i*i<X;i++){
        	
        	long pow = i*i;
        	
        	for(;pow<X;pow *= i)
        		if(max<pow)
        			max = pow;
        	
        }
        
        System.out.println(max);
		
	}


		

    
}