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: Wrong Answer)

#include <stdio.h>

int main(void)
{
    int N;
    int A[1000000];
    int min;
    int max;

    scanf("%d\n", &N);
    for (int i = 0; i < N; i++)
    {
        scanf("%d", &A[i]);
    }

    max = min = A[0];
    for (int i = 0; i < N; i++)
    {
        if (max < A[i])
        {
            max = A[i];
        }
        else if (min > A[i])
        {
            min = A[i];
        }
    }
    printf("%d\n", max - min);
    return 0;
}