class Utils
{
    public static int Greater(int a, int b)
    {
        if (a > b)
            return a;
        else 
            return b;
    }

    public static void Swap(ref int a, ref int b)
    {
        int temp = a;
        a = b;
        b = temp;
    }

    public static bool Factorial(int n, out int answer)
    {
        int k; 
        int f = 1;
        bool ok = true;
        
        try 
        {
            checked
            {
                for (k = 2; k <= n; ++k)
                {
                    f = f * k;
                }
            }
        }
        catch (Exception)
        {
            f = 0;
            ok = false;
        }

        answer = f;
        return ok;
    }

}