diff --git a/HW2_three files/README.md b/HW2_three files/README.md
index 2628fa0756e427122301b314165962f008808584..3bb4079314139d13154b3ea93578e0d2ac491feb 100644
--- a/HW2_three files/README.md	
+++ b/HW2_three files/README.md	
@@ -1,24 +1,24 @@
-#CPP
+# CPP
 - include file
     -- ex) #include <stdio.h> or "file.h"
 
 - Conditional Complication
-    -- #if, #ifdef, #ifndef, #elif, #else, #endif
+    - #if, #ifdef, #ifndef, #elif, #else, #endif
 
-#GCC compile option
--c: generate .o file
--g: for debeg
--O: optimization
+# GCC compile option
+- -c: generate .o file
+- -g: for debeg
+- -O: optimization
 
-#GCC compile - for multiple file
+# GCC compile - for multiple file
 - ex) func.h, func.c, main.c
-    --compile -gcc main.c func.c
+    - compile -gcc main.c func.c
 
 
-###project HW2###
+# project HW2
 
-#GCC compile -- by using preprocessor
+## GCC compile -- by using preprocessor
 - #ifdef, #else, #endif
-    -- func.c에서 int func_name_or_id() 구현 (no using #define PRINT_ID)
-    -- difference between gcc -DPRINT_ID main.c func.c and gcc main.c func.c
-    -- gcc -DPRINT_ID는 PRINT_ID가 정의된 상태로 컴파일 되므로 #ifdef 실행
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+    - func.c에서 int func_name_or_id() 구현 (no using #define PRINT_ID)
+    - difference between gcc -DPRINT_ID main.c func.c and gcc main.c func.c
+    - gcc -DPRINT_ID는 PRINT_ID가 정의된 상태로 컴파일 되므로 #ifdef 실행
\ No newline at end of file