Some reorg so I can have the original inputs

Day1/Day1.cs

@@ -0,0 +1,47 @@
+using System;
+using System.IO;
+
+namespace Advent
+{
+    public static class Day1
+    {
+        public static void Execute()
+        {
+            var lines = File.ReadAllLines(@".\Day1\input.txt");
+
+            var total = 0.0;
+
+            foreach (var line in lines)
+            {
+                var mass = double.Parse(line);
+
+                var fuel = CalculateFuel(mass);
+
+                total += fuel;
+            }
+
+            Console.WriteLine(total);
+        }
+
+        private static double CalculateFuel(double mass)
+        {
+            var totalFuel = 0.0;
+
+            var fuel = Math.Floor(mass / 3) - 2;
+
+            totalFuel += fuel;
+
+            while (fuel > 2)
+            {
+                fuel = Math.Floor(fuel / 3) - 2;
+
+                if (fuel < 0)
+                    fuel = 0;
+
+                totalFuel += fuel;
+            }
+
+            return totalFuel;
+        }
+    }
+}