diff --git a/makefile b/makefile
index c82fd2e..f61948b 100644
--- a/makefile
+++ b/makefile
@@ -1,9 +1,10 @@
 SOURCE = $(shell ls notebooks/*/*.py)
 NOTEBOOKS = $(SOURCE:.py=.ipynb)
 GENERATOR = $(abspath ./tools/gen_questions.py)
+
 all: $(NOTEBOOKS)
 
-%.ipynb %.py:
+%.ipynb: %.py $(GENERATOR)
 	cd $(dir $*); python3 $(GENERATOR) $(notdir $*)
 
 clean: