diff --git a/2021/RESULTS.txt b/2021/RESULTS.txt
index 9bb95fb..442d1ba 100644
--- a/2021/RESULTS.txt
+++ b/2021/RESULTS.txt
@@ -277,3 +277,15 @@ aoc-c : res=606484
 aoc-c : res=1162571910364852
 	time: 0:00.19 real, 0.18 user, 0.00 sys
 	context-switch:	17+1, page-faults: 0+973
+
+=========================================
+================= day24 =================
+=========================================
+
+aoc-c : res=98998519596997
+	time: 0:00.02 real, 0.02 user, 0.00 sys
+	context-switch:	2+1, page-faults: 0+89
+
+aoc-c : res=31521119151421
+	time: 0:00.40 real, 0.40 user, 0.00 sys
+	context-switch:	1+1, page-faults: 0+85
diff --git a/2021/day23/aoc-c.c b/2021/day23/aoc-c.c
index 7805ec9..69fcaa8 100644
--- a/2021/day23/aoc-c.c
+++ b/2021/day23/aoc-c.c
@@ -35,15 +35,25 @@ static const u64 cost[] = {
     1, 10, 100, 1000
 };
 
-/* bitboards usage:
- *
- *
+/*
  * #############
  * #abcdefghijk#
  * ###l#m#n#o###
  *   #p#q#r#s#
  *   #########
  *
+ * From initial position, we can go:
+ *   - to a, b, d, f, h, j, k
+ *   - to destination room if room unlocked
+ * To unlock a room:
+ *   - Room must be empty or contain only correct amphipods
+ *
+ *
+ *
+ * From a, b, d, f, h, j, k, we can go only to correct unlocked room
+ *
+ * Init:
+ * from start position
  * bit 63: a
  * bit 62: b
  * bit 61: c
@@ -97,7 +107,7 @@ pos_t *pos_zero;
 
 static inline u64 get_occupancy(pos_t *pos)
 {
-    return pos->amp[0] | pos->amp[1] | pos->amp[2] | pos->amp[3];
+    return pos->amp[A] | pos->amp[B] | pos->amp[C] | pos->amp[D];
 }
 
 /* here we allow mask to be in forbidden places
diff --git a/2021/day24/EXAMPLE.txt b/2021/day24/EXAMPLE.txt
deleted file mode 100644
index 6b1b0e6..0000000
--- a/2021/day24/EXAMPLE.txt
+++ /dev/null
@@ -1,11 +0,0 @@
-inp w
-add z w
-mod z 2
-div w 2
-add y w
-mod y 2
-div w 2
-add x w
-mod x 2
-div w 2
-mod w 2
diff --git a/2021/day24/EXAMPLE1.txt b/2021/day24/EXAMPLE1.txt
deleted file mode 100644
index a41747d..0000000
--- a/2021/day24/EXAMPLE1.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-inp x
-mul x -1
diff --git a/2021/day24/EXAMPLE2.txt b/2021/day24/EXAMPLE2.txt
deleted file mode 100644
index ae8792a..0000000
--- a/2021/day24/EXAMPLE2.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-inp z
-inp x
-mul z 3
-eql z x
diff --git a/2021/day24/README.txt b/2021/day24/README.txt
index d5c4c9b..e37a5ce 100644
--- a/2021/day24/README.txt
+++ b/2021/day24/README.txt
@@ -59,4 +59,11 @@ MONAD imposes additional, mysterious restrictions on model numbers, and legend s
 
 To enable as many submarine features as possible, find the largest valid fourteen-digit model number that contains no 0 digits. What is the largest model number accepted by MONAD?
 
-To begin, get your puzzle input.
+Your puzzle answer was 98998519596997.
+--- Part Two ---
+
+As the submarine starts booting up things like the Retro Encabulator, you realize that maybe you don't need all these submarine features after all.
+
+What is the smallest model number accepted by MONAD?
+
+Your puzzle answer was 31521119151421.