Add day 2

Days/Day1.cs

@@ -11,7 +11,7 @@ public class Day1 : Day
     {
         int currentCalories = 0;
         int maxCalories = 0;
-        foreach (var line in Input.Split('\n'))
+        foreach (var line in Input.ReadAllLines())
         {
             // Next elf on empty line
             if (string.IsNullOrWhiteSpace(line))
@@ -36,7 +36,7 @@ public class Day1 : Day
         var elfCalories = new List<int>();
     
         int currentCalories = 0;
-        foreach (var line in Input.Split('\n'))
+        foreach (var line in Input.ReadAllLines())
         {
             // Next elf on empty line
             if (string.IsNullOrWhiteSpace(line))

StringExtensions.cs

@@ -0,0 +1,17 @@
+namespace AdventOfCode;
+
+public static class StringExtensions
+{
+    public static IEnumerable<string> ReadAllLines(this StringReader reader)
+    {
+        while (reader.ReadLine() is { } line)
+        {
+            yield return line;
+        }
+    }
+
+    public static IEnumerable<string> ReadAllLines(this string text)
+    {
+        return new StringReader(text).ReadAllLines();
+    }
+}