diff --git a/src/Year_2015/P11.py b/src/Year_2015/P11.py
index 4d93578..949fa48 100644
--- a/src/Year_2015/P11.py
+++ b/src/Year_2015/P11.py
@@ -57,15 +57,16 @@ def rule_1(chars: list[str]) -> bool:
 
 
 def rule_2(chars: list[str], pos: int) -> list[str]:
-    # not contain the letters i, o, or l
+    # try with next letter
     a = ord(chars[pos]) + 1
-    # rule # 2
+    # not contain the letters i, o, or l
     if a in forbidden_chars:
         a += 1
     # wraps around to a
     if a > 122:
         a = 97
         chars[pos] = chr(a)
+        # change now previous letter also
         rule_2(chars, pos - 1)
     else:
         chars[pos] = chr(a)