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.lang.reflect.Array;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;


class Main {
    public static void main(String[] args) {
    	Scanner sc = new Scanner(System.in);
    	int x = sc.nextInt();
    	int xx = x / 2;
    	int ans = 0;

    	for(int i = 0; i <= x; i++){
    		for(int j = 0; j <= x; j++){
    			if(Math.pow(i, j) > ans && Math.pow(i, j) <= x) ans = (int)Math.pow(i, j);
    		}
    	}

    	System.out.println(ans);
    }
}