diff --git a/day19/ex2.bash b/day19/ex2.bash
index cd2c992..99b30cd 100755
--- a/day19/ex2.bash
+++ b/day19/ex2.bash
@@ -69,20 +69,20 @@ done
 
 
 # hack:
-# 1) build part 1 tree
+# 1) build rules 42 and 31
 # 2) calculate rule 8 and 11 with some "guessed" minimum possible value
-# 3) rebuild tree from scratch, but with rules 8 and 11 pre-loaded
-buildtree 1 var_0 0
+# 3) build rule 0
 
-# This value was found manually: stable from 5.
+# result starts to be "stable" from this value
 SOME_LIMIT=5
+
+buildtree 1 var_0 42
+buildtree 1 var_0 31
 tmp8="(${MATCH[42]})+"
 tmp11="(${MATCH[42]}${MATCH[31]})"
 for ((i=2; i<SOME_LIMIT; ++i)); do
     tmp11+="|((${MATCH[42]}){$i}(${MATCH[31]}){$i})"
 done
-
-MATCH=()
 MATCH[8]="$tmp8"
 MATCH[11]="($tmp11)"
 buildtree 1 var_0 0
@@ -93,5 +93,3 @@ for str in "${STRING[@]}"; do
 done
 
 printf "%s : res=%d\n" "$CMD" "$res"
-
-exit 0