这段代码哪里错了

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{
    class Program
    {
        delegate double ProcessDelegate(double param1, double param2);
        static double Multiply(double param1, double param2)
        {
            return param1 * param2;
        }
        static double Divide(double param1, double param2)
        {
            return param1 / param2;
        }
        static void Main(string[] args)
        {
            ProcessDelegate process;
            string input = Console.ReadLine();
            int commaPos = input.IndexOf(',');
            double param1=Convert.ToDouble(input.Substring(0,commaPos));
            double param2=Convert.ToDouble(input.Substring(commaPos+1,
                                                   input.Length-commaPos-1));
            input = Console.ReadLine();
            if (input == "M")
                process = new ProcessDelegate(Multiply);
            else ;
            Console.WriteLine(process(param1,param2));

        }
    }
}
这段代码哪里错了 编译器错误显示"使用了未赋值的局部变量process"
就这唯一一个错误