Problem:
Score : 100 points

Problem Statement

You are given a positive integer N.
Find the minimum positive integer divisible by both 2 and N.

Constraints

1 \leq N \leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N

Output

Print the minimum positive integer divisible by both 2 and N.

Sample Input 1

3

Sample Output 1

6

6 is divisible by both 2 and 3.
Also, there is no positive integer less than 6 that is divisible by both 2 and 3.
Thus, the answer is 6.

Sample Input 2

10

Sample Output 2

10

Sample Input 3

999999999

Sample Output 3

1999999998

Solution in Java (OpenJDK 11.0.6) (judge verdict: Runtime Error)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] numbers = new int[N];
		
		for(int j = 0; j <numbers.length; j++) {
			numbers[j] = sc.nextInt();
		}
		
		int max = numbers[0];
		int min = numbers[0];
		
		for(int i = 1; i < numbers.length; i++ ) {
			if(numbers[i] > max ) {
				max = numbers[i];
			}
			if(numbers[i] < min ) {
				min = numbers[i];
			}
		}
		System.out.println(max-min);
	}

}