class Program
        
    {
        const double PIE = 3.14159;

        static void Main(string[] args)
        {
           
            int num = 5;
            Console.WriteLine
                ("The factorial of {0} is {1}.", num, factorial(num));
            double radius = 5;
            Console.WriteLine
                ("The area of a circle with radius {0} is {1}.", radius, area(radius));

            int a = 15;
            int b = 3;
            int c = 6;

           if (hasRemainder(a, b))
                Console.WriteLine
                    ("{0} / {1} has a remainder.", a, b);
            else
                Console.WriteLine
                    ("{0} / {1} does not have a remainder.", a, b);

            if (hasRemainder(a, c))
                Console.WriteLine
                    ("{0} / {1} has a remainder.", a, c);
            else
                Console.WriteLine
                    ("{0} / {1} does not have a remainder.", a, c);           
        }

        public static int factorial(int a)
        {
            int result = 1;
            for (int I = 2; I <= a; I++)
            {
                result *= I;
            }
            return result;
        }

        public static double area(double radius)
        {
            return PIE * radius * radius;
        }

        public static int hasRemainder (int a, int b)
        {
            return (a%b);
        }
    }