diff --git a/day_04/common.nim b/day_04/common.nim
new file mode 100644
index 0000000..9c4b599
--- /dev/null
+++ b/day_04/common.nim
@@ -0,0 +1,32 @@
+import std/[math, sequtils, setutils, strformat, strmisc, strutils]
+
+# ASSUMPTION: lottery numbers are < 128
+type
+    Card* = ref object
+        idx*: int
+        play, pot: set[int8]
+
+proc value*(card: Card): int =
+    (card.play * card.pot).len
+
+proc points*(card: Card): int =
+    result = case card.value:
+        of 0: 0
+        of 1: 1
+        else: 2 ^ (card.value - 1)
+
+proc `$`*(card: Card): string =
+    return &"Card {card.idx+1}: {card.play}, {card.pot} => {card.value}"
+
+proc parseNumberSet(s: string): set[int8] =
+     s.strip.splitWhitespace().mapIt(it.parseInt.int8).toSet
+
+proc parseInput*(s: string): seq[Card] =
+    let lines = s.strip.splitLines
+    for i, line in lines:
+        let card = new Card
+        let (left, _, right) = line.split(":")[1].partition("|")
+        card.idx = i
+        card.play = parseNumberSet(left)
+        card.pot = parseNumberSet(right)
+        result.add(card)
diff --git a/day_04/solution_04a.nim b/day_04/solution_04a.nim
index c97ab51..19cba85 100644
--- a/day_04/solution_04a.nim
+++ b/day_04/solution_04a.nim
@@ -1,37 +1,11 @@
-import std/[cmdline, math, sequtils, setutils, strformat, strscans, strutils]
+import std/[cmdline, math, sequtils, strformat]
+
+import common
 
-var result = 0
 var fn = if paramCount() > 0: paramStr(1) else: "input_04.txt"
-var lines = readFile(fn).strip.splitLines
-
-# ASSUMPTION: lottery numbers are < 128
-type
-    Card = ref object
-        play, pot: set[int8]
-var cards: seq[Card]
-
-proc points(card: Card): int =
-    let matches = (card.play * card.pot).len
-    if matches == 1:
-        result = 1
-    elif matches > 1:
-        result = 2 ^ (matches - 1)
-    else:
-        result = 0
-
-
-for line in lines:
-    var cardno: int
-    let cardspec = line.split(":", 1)
-
-    if scanf(cardspec[0].strip, "Card$s$i", cardno):
-        let card = new Card
-        card.play = cardspec[1].split("|")[0].strip.splitWhitespace().mapIt(it.strip).mapIt(it.parseInt).mapIt(it.int8).toSet
-        card.pot = cardspec[1].split("|")[1].strip.splitWhitespace().mapIt(it.strip).mapIt(it.parseInt).mapIt(it.int8).toSet
-        echo &"Card {cardno}: {card.play}, {card.pot} => {card.points}"
-        cards.add(card)
-        result += card.points
 
+var cards = parseInput(readFile(fn))
+var result = sum(cards.mapIt(it.points))
 echo &"Cards processed: {cards.len}"
 echo &"Result: {result}"
 
diff --git a/day_04/solution_04b.nim b/day_04/solution_04b.nim
index e41922f..0bfe48e 100644
--- a/day_04/solution_04b.nim
+++ b/day_04/solution_04b.nim
@@ -1,36 +1,12 @@
-import std/[cmdline, sequtils, setutils, strformat, strscans, strutils]
+import std/[cmdline, strformat]
+
+import common
 
-var result = 0
 var fn = if paramCount() > 0: paramStr(1) else: "input_04.txt"
-var lines = readFile(fn).strip.splitLines
-
-# ASSUMPTION: lottery numbers are < 128
-type
-    Card = ref object
-        idx: int
-        play, pot: set[int8]
-var cards: seq[Card]
-
-proc value(card: Card): int =
-    (card.play * card.pot).len
-
-#proc `$`(card: Card): string =
-#    return &"Card idx={card.idx}: value={card.value}"
-
-
-for i, line in lines:
-    var cardno: int
-    let cardspec = line.split(":", 1)
-
-    if scanf(cardspec[0].strip, "Card$s$i", cardno):
-        let card = new Card
-        card.idx = i
-        card.play = cardspec[1].split("|")[0].strip.splitWhitespace().mapIt(it.strip).mapIt(it.parseInt).mapIt(it.int8).toSet
-        card.pot = cardspec[1].split("|")[1].strip.splitWhitespace().mapIt(it.strip).mapIt(it.parseInt).mapIt(it.int8).toSet
-        #echo &"Card {card.idx}: {card.play}, {card.pot} => {card.value}"
-        cards.add(card)
-
+var cards = parseInput(readFile(fn))
 var stack = cards
+var result = 0
+
 while stack.len > 0:
     result += len(stack)
     var extra_cards: seq[Card]
@@ -41,7 +17,7 @@ while stack.len > 0:
 
     stack = extra_cards
 
-#echo &"Cards processed: {cards.len}"
+echo &"Cards processed: {cards.len}"
 echo &"Result: {result}"
 
 case fn: