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;

class Main{
	public static void main(String args[]){
		int x, a, b, c;
		int n = 1;
		c = 1;
		Scanner sc = new Scanner(System.in);
		x = sc.nextInt();
		if(x == 1){
			System.out.print(1);
			return;
		}
		for(int i = 2; i <= 32; i++){
			b = i;
			while(c * b <= x){
              c *= b;
			  if(n <= c){
				  n = c;
			  }
			}
		}
		System.out.print(n);
	}
}