diff --git a/README.md b/README.md
index 31f7dc3..bdbbba7 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
 
 A little plane in 3d for CASIO Graph 35+eII PythonExtra and Python.
 
-mainx.py -> CASIO Python app version
+mainX.py -> CASIO Python app version
+
 mainPEx.py -> PythonExtra version
+
 mainPExO.py -> PythonExtra opt_level(3) version
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