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: Runtime Error)

#include<stdio.h>

int main(void)
{
 int max,min,n;
 int tmp,i,s[100];

 scanf("%d",&n);

 for(i=0;i<n;i++){
  scanf("%d",&s[i]);
 }
 max=s[0];
 min=s[0];

 for(i=0;i<n;i++){
   if(max<s[i]) max=s[i];
 else if(min>s[i]) max=s[i];
 }

 tmp=max-min;
 printf("%d\n",tmp);

 return 0;
}