diff --git a/adventofcode.cabal b/adventofcode.cabal
index 274b6f1..dfbe447 100644
--- a/adventofcode.cabal
+++ b/adventofcode.cabal
@@ -2,7 +2,7 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: d871caa5723224d888f552d659e29f2e860d791e12ad0c0d7ced450d2334b83d
+-- hash: 877996d6cd90e6a9a1d5d7f01e79fd91225f46e4cf930943da73fad95dda8ea0
 
 name:                adventofcode
 version:             0.1.0.0
@@ -47,8 +47,8 @@ library
       Day15
       Day16
       Day17
-  other-modules:
       Day18
+  other-modules:
       Permutations
       Paths_adventofcode
   build-depends:
diff --git a/app/Main.hs b/app/Main.hs
index 547069f..378ebdf 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -25,6 +25,7 @@ import qualified Day14
 import qualified Day15
 import qualified Day16
 import qualified Day17
+import qualified Day18
 
 showSol :: [Char] -> Doc -> IO ()
 showSol txt d = putText . toS . render $
@@ -55,6 +56,7 @@ solutions = Map.fromList [(["01"], day01)
                          ,(["15"], day15)
                          ,(["16"], day16)
                          ,(["17"], day17)
+                         ,(["18"], day18)
                          ]
 
 
@@ -204,3 +206,15 @@ day17 = do
   showSol "Solution 1" (int (fromMaybe 0 sol1))
   let sol2 = Day17.solution2 50000000 Day17.input
   showSol "Solution 2" (int sol2)
+
+day18 :: IO ()
+day18 = do
+  putText "Day 18:"
+  minput <- Day18.parseInput
+  case minput of
+    Nothing -> putText "parsing error!"
+    Just input -> do
+      let sol1 = Day18.solution1 input
+      showSol "Solution 1" (int (fromMaybe 0 sol1))
+      let sol2 = Day18.solution2 input
+      showSol "Solution 2" (int sol2)
diff --git a/package.yaml b/package.yaml
index 143b861..7f9e37e 100644
--- a/package.yaml
+++ b/package.yaml
@@ -30,6 +30,7 @@ library:
   - Day15
   - Day16
   - Day17
+  - Day18
   dependencies:
   - base >=4.7 && <5
   - protolude
diff --git a/src/Day18.hs b/src/Day18.hs
index 2ac0006..fd94797 100644
--- a/src/Day18.hs
+++ b/src/Day18.hs
@@ -148,12 +148,12 @@ data Instruction =
   | Jgz Value Value
   deriving (Show)
 
-parseInput :: IO Program
+parseInput :: IO (Maybe Program)
 parseInput = parseTxt <$> readFile "inputs/day18.txt"
 
-parseTxt :: Text -> Program
+parseTxt :: Text -> Maybe Program
 parseTxt txt = let instr = txt & T.lines & map (parseInstr . T.words) in
-  listArray (0,length instr-1) instr
+  fmap (listArray (0,length instr-1)) (sequenceA instr)
 
 txtToInt :: Text -> Maybe Int
 txtToInt = fmap fst . head . reads . toS
@@ -162,15 +162,15 @@ parseValue :: Text -> Value
 parseValue t = let c = T.head t in
   if C.isLetter c then R (Reg t) else I (fromMaybe 0 (txtToInt t))
 
-parseInstr :: [Text] -> Instruction
-parseInstr ["snd",v]     = Snd (parseValue v)
-parseInstr ["set",r,v]   = Set (Reg r) (parseValue v)
-parseInstr ["add",r,v]   = Add (Reg r) (parseValue v)
-parseInstr ["mul",r,v]   = Mul (Reg r) (parseValue v)
-parseInstr ["mod",r,v]   = Mod (Reg r) (parseValue v)
-parseInstr ["rcv",r]     = Rcv (Reg r)
-parseInstr ["jgz",v1,v2] = Jgz (parseValue v1) (parseValue v2)
-parseInstr _             = error "Don't knwow this instruction"
+parseInstr :: [Text] -> Maybe Instruction
+parseInstr ["snd",v]     = Just $ Snd (parseValue v)
+parseInstr ["set",r,v]   = Just $ Set (Reg r) (parseValue v)
+parseInstr ["add",r,v]   = Just $ Add (Reg r) (parseValue v)
+parseInstr ["mul",r,v]   = Just $ Mul (Reg r) (parseValue v)
+parseInstr ["mod",r,v]   = Just $ Mod (Reg r) (parseValue v)
+parseInstr ["rcv",r]     = Just $ Rcv (Reg r)
+parseInstr ["jgz",v1,v2] = Just $ Jgz (parseValue v1) (parseValue v2)
+parseInstr _             = Nothing
 
 testInput :: Text
 testInput = "set a 1\n\