static void Main(string[] args)
        {
            string[] str = new string[3];
            str[0] = "12,34";
            str[1] = "c,d";
            str[2] = "d,f";
            Matrix m = new Matrix(str[0].Split(','));
            for (int i = 1; i < str.Length; i++)
            {
                m = m.Multiply(new Matrix(str[i].Split(',')));
            }
            foreach (string s in m.element)
            {
                Console.WriteLine(s);
            }
        }
        struct Matrix
        {
            public string[] element;
            public Matrix(string[] s)
            {
                element = s;
            }
            public Matrix Multiply(Matrix m)
            {
                string[] s = new string[this.element.Length * m.element.Length];
                int index = 0;
                for (int i = 0; i < this.element.Length; i++)
                {
                    for (int j = 0; j < m.element.Length; j++)
                    {
                        s[index] = this.element[i] + "," + m.element[j];
                        index++;
                    }
                }
                return new Matrix(s);
            }
        }