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 C (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include<stdio.h>
#include <string.h>
#include <stdlib.h>

int main (){
  
 int a,b,k,i,j,count,ans;
  scanf("%d",&a);
  
  
  for(i = 1;i < 10000000000;i++){
  	if(i % 2 == 0 && i % a == 0){
    	printf("%d",i);
      	break;
  	}
  }
  

    
  
      return 0;
  
}