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: Time Limit Exceeded)

import java.util.Scanner;
  public class Main{
    public static void main(String[] args){
     Scanner sc = new Scanner(System.in);
     int n = sc.nextInt();
  //  int n =10;
    int max = 999999999;
    int answer = 0;
    for(int i = 0;i<max;i++){
      if(i == 0){

      }else if((i%n == 0) && (i%2 == 0)){
        answer = i;
        break;
      }
    }
    System.out.println(answer);
  }
}