c# 求最小公倍數

class Program
    {
        static void Main(string[] args)
        {
            int n = m(20, 15);
            System.Console.WriteLine("最小公倍數為:" + n.ToString());
            System.Console.Read();
        }

        static int f(int a, int b)//最大公約數 
        {
            if (a < b) { a = a + b; b = a - b; a = a - b; }
            return (a % b == 0) ? b : f(a % b, b);
        }

        static int m(int a, int b)//最小公倍數 
        {
            return a * b / f(a, b);
        }
    }