diff --git a/Makefile b/Makefile
index a580f3b..0a47170 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,8 @@ ALL = *.java
 .PHONY: run clean docs
 
 run:
+	$(RM) build/*
+	$(RM) docs/*
 	$(JAVAC) $(OPTION_COMPILE) $(API)/$(ALL) $(MNP)/$(ALL) $(TEST)/$(ALL)
 	cp -r src/Test/libs build/Test && cd build/ && $(JAVA) $(OPTION_EXE)