diff --git a/Day6.cs b/Day6.cs
index 36e3c81..11a439b 100644
--- a/Day6.cs
+++ b/Day6.cs
@@ -1,5 +1,6 @@
 #define Day6
 #if Day6
+using System.Diagnostics;
 var fish = File.ReadAllText("day6/input").Split(",")
     .Select(long.Parse)
     .GroupBy(x => x)
@@ -31,4 +32,17 @@ Dictionary<long, long> Copy(Dictionary<long, long> dict) {
     return dict.ToDictionary(entry => entry.Key,
         entry => entry.Value);
 }
+
+// O(n)
+long[] fishAsArray = fish.OrderBy(x => x.Key).Select(x => x.Value).ToArray();
+int i = 0;
+int days = 256;
+int spawn = 6;
+while (days > 0) {
+    int newSpawn = (i + 7) % 9;
+    fishAsArray[newSpawn] += fishAsArray[i];
+    i = (i + 1) % 9;
+    days--;
+}
+Console.WriteLine(fishAsArray.Sum());
 #endif
\ No newline at end of file