diff --git a/2021/four.nim b/2021/four.nim
index d588d96..41645ac 100644
--- a/2021/four.nim
+++ b/2021/four.nim
@@ -1,60 +1,64 @@
-import std/[strutils, sequtils, options, math, parseutils, sets]
+import std/[strutils, sequtils, options, math, parseutils, sets, strformat]
 import ./common
 
 type Board = object
   entries: seq[string]
   checked: seq[int]
 
-let winningSets = [
-  [0, 1, 2, 3, 4],
-  [5, 6, 7, 8, 9],
-  [10, 11, 12, 13, 14],
-  [15, 16, 17, 18, 19],
-  [20, 21, 22, 23, 24],
-  [0, 5, 10, 15, 20],
-  [1, 6, 11, 16, 21],
-  [2, 7, 12, 17, 22],
-  [3, 8, 13, 18, 23],
-  [4, 9, 14, 19, 24]
-].mapIt(it.toHashSet())
+proc isBoardWinning(b: Board): bool =
+  let winningSets: seq[HashSet[int]] = [
+    [0, 1, 2, 3, 4],
+    [5, 6, 7, 8, 9],
+    [10, 11, 12, 13, 14],
+    [15, 16, 17, 18, 19],
+    [20, 21, 22, 23, 24],
+    [0, 5, 10, 15, 20],
+    [1, 6, 11, 16, 21],
+    [2, 7, 12, 17, 22],
+    [3, 8, 13, 18, 23],
+    [4, 9, 14, 19, 24]
+  ].mapIt(it.toHashSet())
 
-proc isBoardWinning(b: ref Board): bool =
   let s = b.checked.toHashSet()
   for w in winningSets:
     if w < s:
       return true
   return false
 
-
 proc squidBingo(inputLines: seq[string]): int =
   var input: seq[string] = inputLines
   let calledNumbers: seq[string] = input[0].split ','
   input.delete 0..1
 
-  echo calledNumbers
-
   # construct boards
   var boards: seq[Board]
   var board: Board = Board(entries: @[], checked: @[])
   for l in input:
-    echo l
     if l.strip() == "":
       boards.add board
-      echo board.entries
       board = Board(entries: @[], checked: @[])
       continue
     board.entries.add [l[0..1], l[3..4], l[6..7], l[9..10], l[12..13]].mapIt(it.strip())
-    
+
+  boards.add board
+
+  echo boards
+
   for n in calledNumbers:
-    for b in boards:
+    echo n
+    for b in boards.mitems():
       for i, e in b.entries:
         if n == e:
           # TODO: why can't I add here but I can add on 46?!
           b.checked.add i
+      echo b.entries, b.checked
       if b.isBoardWinning():
-        # TODO: get unchecked entries
-        # TODO: multiple their sum with last .checked
-        return 9
+        var entriesSum = 0
+        for i, v in b.entries:
+          if not (i in b.checked): entriesSum += v.parseInt()
+          else: echo &"{i} {v}"
+        echo &"{entriesSum} * {n} = {entriesSum * n.parseInt()}"
+        return entriesSum * n.parseInt()
 
   return 0
 
diff --git a/2021/readme.md b/2021/readme.md
index 571f558..120fdd0 100644
--- a/2021/readme.md
+++ b/2021/readme.md
@@ -40,7 +40,7 @@ Or
 
 - [x] [Day 1](./1.ts)
 - [x] [Day 2](./2.ts)
-- [ ] Day 3
+- [x] [Day 3](./3.ts)
 - [ ] Day 4
 - [ ] Day 5
 - [ ] Day 6