Metric Convert

using System;

namespace MetricConvert
{
    class Program
    {
        static void Main(string[] args)
        {
            double size = double.Parse(Console.ReadLine());
            var sourceMetric = Console.ReadLine().ToLower();
            var distMetric = Console.ReadLine().ToLower();
            var resultSource = 0.0;

            switch (sourceMetric)
            {
                case "km": resultSource = size / 0.001; break;
                case "ft": resultSource = size / 3.2808399; break;
                case "yd": resultSource = size / 1.0936133; break;
                case "in": resultSource = size / 39.3700787; break;
                case "mi": resultSource = size / 0.000621371192; break;
                case "cm": resultSource = size / 100; break;
                case "mm": resultSource = size / 1000; break;
                case "m": resultSource = size / 1; break;

            }
            switch (distMetric)
            {
                case "km": resultSource *= 0.001; break;
                case "ft": resultSource *= 3.2808399; break;
                case "yd": resultSource *= 1.0936133; break;
                case "in": resultSource *= 39.3700787; break;
                case "mi": resultSource *= 0.000621371192; break;
                case "cm": resultSource *= 100; break;
                case "mm": resultSource *= 1000; break;
                case "m": resultSource *= 1; break;
            }
            Console.WriteLine(resultSource);
        }
    }
}