diff --git a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/Day12.fs b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/Day12.fs
index df5bb30..3ac1f18 100644
--- a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/Day12.fs
+++ b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/Day12.fs
@@ -8,38 +8,51 @@ open System.Globalization
 module Day12 =
 
     let rec solve (line : ReadOnlySpan<char>) (groups : IReadOnlyList<int>) (currentGroupIndex : int) =
+        if line.Length = 0 then
+            if currentGroupIndex = groups.Count then LanguagePrimitives.GenericOne else LanguagePrimitives.GenericZero
+        else
         match line.[0] with
         | '#' ->
-            if currentGroupIndex >= groups.Count then 0 else
+            if currentGroupIndex >= groups.Count then LanguagePrimitives.GenericZero else
             let mutable isOk = true
             for i = 1 to groups.[currentGroupIndex] - 1 do
-                if isOk && line.[i] <> '#' && line.[i] <> '?' then
+                if isOk && (i >= line.Length || (line.[i] <> '#' && line.[i] <> '?')) then
                     isOk <- false
-            if not isOk then 0 else
-            if line.[groups.[currentGroupIndex]] = '#' then 0 else
-            solve (line.Slice (groups.[currentGroupIndex] + 1)) groups (currentGroupIndex + 1)
+            if not isOk then LanguagePrimitives.GenericZero else
+            if groups.[currentGroupIndex] < line.Length then
+                if line.[groups.[currentGroupIndex]] = '#' then
+                    LanguagePrimitives.GenericZero
+                else
+                    solve (line.Slice (groups.[currentGroupIndex] + 1)) groups (currentGroupIndex + 1)
+            else
+                solve ReadOnlySpan<_>.Empty groups (currentGroupIndex + 1)
         | '.' ->
             solve (line.Slice 1) groups currentGroupIndex
         | '?' ->
             let ifDot = solve (line.Slice 1) groups currentGroupIndex
             let ifHash =
-                if currentGroupIndex >= groups.Count then 0 else
+                if currentGroupIndex >= groups.Count then LanguagePrimitives.GenericZero else
                 let mutable isOk = true
                 for i = 1 to groups.[currentGroupIndex] - 1 do
-                    if isOk && line.[i] <> '#' && line.[i] <> '?' then
+                    if isOk && (i >= line.Length || (line.[i] <> '#' && line.[i] <> '?')) then
                         isOk <- false
-                if not isOk then 0 else
-                if line.[groups.[currentGroupIndex]] = '#' then 0 else
-                solve (line.Slice (groups.[currentGroupIndex] + 1)) groups (currentGroupIndex + 1)
+                if not isOk then LanguagePrimitives.GenericZero else
+                if groups.[currentGroupIndex] < line.Length then
+                    if groups.[currentGroupIndex] < line.Length && line.[groups.[currentGroupIndex]] = '#' then
+                        LanguagePrimitives.GenericZero
+                    else
+                        solve (line.Slice (groups.[currentGroupIndex] + 1)) groups (currentGroupIndex + 1)
+                else
+                    solve ReadOnlySpan<_>.Empty groups (currentGroupIndex + 1)
             ifDot + ifHash
         | _ ->
-            if currentGroupIndex = groups.Count then 1 else 0
+            if currentGroupIndex = groups.Count then LanguagePrimitives.GenericOne else LanguagePrimitives.GenericZero
 
 
     let part1 (s : string) =
         use mutable lines = StringSplitEnumerator.make '\n' s
 
-        let mutable answer = 0
+        let mutable answer = 0uL
         let arr = ResizeArray ()
         for line in lines do
             if not line.IsEmpty then
@@ -56,4 +69,22 @@ module Day12 =
     let part2 (s : string) =
         use mutable lines = StringSplitEnumerator.make '\n' s
 
-        -1
+        let mutable answer = 0uL
+        let arr = ResizeArray ()
+        for line in lines do
+            if not line.IsEmpty then
+                arr.Clear ()
+                let spaceIndex =line.IndexOf ' '
+                for _ = 0 to 4 do
+                    use ints = StringSplitEnumerator.make' ',' (line.Slice (spaceIndex + 1))
+                    for int in ints do
+                        arr.Add (Int32.Parse (int, NumberStyles.None, CultureInfo.InvariantCulture))
+
+                let sliced = line.Slice(0, spaceIndex).ToString ()
+                let line = String.Concat (sliced, '?', sliced, '?', sliced, '?', sliced, '?', sliced)
+
+                let solved = solve (line.AsSpan()) arr 0
+                printfn $"%s{line} : %i{solved}"
+                answer <- answer + solved
+
+        answer
diff --git a/AdventOfCode2023.FSharp/Test/TestDay12.fs b/AdventOfCode2023.FSharp/Test/TestDay12.fs
index 30d412c..3245ade 100644
--- a/AdventOfCode2023.FSharp/Test/TestDay12.fs
+++ b/AdventOfCode2023.FSharp/Test/TestDay12.fs
@@ -12,13 +12,13 @@ module TestDay12 =
 
     [<Test>]
     let part1Sample () =
-        sample |> Day12.part1 |> shouldEqual 21
+        sample |> Day12.part1 |> shouldEqual 21uL
 
     [<Test>]
     let part2Sample () =
         sample
         |> Day12.part2
-        |> shouldEqual 0
+        |> shouldEqual 525152uL
 
     [<Test>]
     let part1Actual () =
@@ -31,7 +31,7 @@ module TestDay12 =
                 Assert.Inconclusive ()
                 failwith "unreachable"
 
-        Day12.part1 s |> shouldEqual 7402
+        Day12.part1 s |> shouldEqual 7402uL
 
     [<Test>]
     let part2Actual () =
@@ -44,4 +44,4 @@ module TestDay12 =
                 Assert.Inconclusive ()
                 failwith "unreachable"
 
-        Day12.part2 s |> shouldEqual 0
+        Day12.part2 s |> shouldEqual 0uL