diff --git a/2021/three.nim b/2021/three.nim
index eca2999..5637f74 100644
--- a/2021/three.nim
+++ b/2021/three.nim
@@ -1,4 +1,4 @@
-import std/[strutils, sequtils, options, math]
+import std/[strutils, sequtils, options, math, parseutils]
 import ./common
 
 const ASCII_ZERO = int('0')
@@ -6,18 +6,18 @@ type BitCounter = object
   zeroes: int
   ones: int
 
-proc countBits(inputs: seq[string], maybeWidth: Option[int], maybeWindow: Option[int]): seq[BitCounter] =
+proc countBits(inputs: seq[string], maybeWidth: Option[int], offset = 0): seq[BitCounter] =
   let width = maybeWidth.get(inputs[0].len())
-  let window = maybeWindow.get(width)
-  let start = (width - window)
-  for i in 0..<window: result.add(BitCounter(zeroes: 0, ones: 0))
+  let maxIndex = offset+width
+  for i in offset..<maxIndex: result.add(BitCounter(zeroes: 0, ones: 0))
   for binstring in inputs:
-    for i in start..<width:
-      if (binstring[i].int() - ASCII_ZERO) > 0: inc result[i - start].ones
-      else: inc result[i - start].zeroes
+    for i in offset..<maxIndex:
+      let outIndex = i - offset
+      if (binstring[i].int() - ASCII_ZERO) > 0: inc result[outIndex].ones
+      else: inc result[outIndex].zeroes
 
 proc powerConsumption(inputs: seq[string]): int =
-  let counters = inputs.countBits(none(int), none(int))
+  let counters = inputs.countBits(none(int))
   let width: Natural = inputs[0].len()
   for i in 0..<width:
     if counters[i].ones > counters[i].zeroes: inc result
@@ -26,10 +26,48 @@ proc powerConsumption(inputs: seq[string]): int =
   result = result * (result xor ((2 ^ width) - 1))
 
 proc lifeSupportRating(inputs: seq[string]): int =
-  return 0
+  let width: Natural = inputs[0].len()
+  var oxygenRating, co2Rating = 0
+  var oxygenCandidates, co2Candidates: seq[int] = toSeq(0..<inputs.len)
+  echo oxygenCandidates, co2Candidates
+  for i in 0..<width:
+    var newOxygenCandidates, newCo2Candidates: seq[int] = @[]
+    if oxygenRating == 0:
+      let candidates = oxygenCandidates.mapIt(inputs[it])
+      let counters = countBits(candidates, some(1), i)
+      let moreCommon: char = if counters[0].ones >= counters[0].zeroes: '1' else: '0'
+      echo "OX: ", i, candidates, moreCommon, counters[0]
+      if counters[0].zeroes == counters[0].ones:
+        echo "SAME OX"
+      for j in oxygenCandidates:
+        if inputs[j][i] == moreCommon:
+          newOxygenCandidates.add(j)
+      if newOxygenCandidates.len() == 1:
+        discard inputs[newOxygenCandidates[0]].parseBin(oxygenRating)
+        echo "OX DONE"
+    if co2Rating == 0:
+      let candidates = co2Candidates.mapIt(inputs[it])
+      let counters = countBits(candidates, some(1), i)
+      let lessCommon: char = if counters[0].zeroes <= counters[0].ones: '0' else: '1'
+      echo "CO2 ", i, candidates, lessCommon, counters[0]
+      if counters[0].zeroes == counters[0].ones:
+        echo "SAME CO2"
+      for j in co2Candidates:
+        if inputs[j][i] == lessCommon:
+          newCo2Candidates.add(j)
+      if newCo2Candidates.len() == 1:
+        discard inputs[newCo2Candidates[0]].parseBin(co2Rating)
+        echo "CO2 DONE"
+    oxygenCandidates = newOxygenCandidates
+    co2Candidates = newCo2Candidates
+    if oxygenRating != 0 and co2Rating != 0: break
+  echo "OX: ", oxygenRating
+  echo "CO2: ", co2Rating
+  return oxygenRating * co2Rating
 
 let input = 3.loadInput()
-time("countBits part 1"): echo input.powerConsumption()
+time("powerConsumption part 1"): echo input.powerConsumption()
+time("lifeSupportRating part 2"): echo input.lifeSupportRating()
 
 when not defined(release):
   static: