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 Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.util.Scanner;
public class Main{
  public static void main(String[] args){
	Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    long max = 0;
    long min = 0;
    for(int i=0; i<N; i++){
      long x = sc.nextInt();
      if(i == 0){ max = x; min = x;}
      else{
        if(x > max) { max = x;}
        if(x < min) { min = x;}
      }
    }
    System.out.println( max - min);  
  }
}