diff --git a/slides/Makefile b/slides/Makefile
index d80a9bf816883231eafaa7b9913c15ec7299fcc4..50ae2dde5f31104674ad2e2d6bfc5a27692c2aeb 100644
--- a/slides/Makefile
+++ b/slides/Makefile
@@ -26,7 +26,7 @@ markdown: $(MARKDOWN)
 %.html: %.md metadata.yaml
 	pandoc -s $(OPTIONS) $(REVEALOPTIONS) -o $@ $^
 
-%.markdown: %.md metadata.yaml
+%.markdown: %.md metadata.yaml yq
 	sed '1 { /^---/ { :a N; /\n---/! ba; d} }' $< > no_header
 	grep -v -F -x -f  no_header $< > header.yaml
 	echo "---" > tmp.yaml
@@ -34,7 +34,9 @@ markdown: $(MARKDOWN)
 	cat tmp.yaml no_header > $@
 	rm no_header header.yaml tmp.yaml
 
-
+yq:
+	wget -nc https://github.com/mikefarah/yq/releases/download/3.4.1/yq_linux_amd64
+	chmod "u+x" yq_linux_amd64 
 
 deploy: all 
 	mkdir -p prog_seq_c_cours
@@ -42,4 +44,4 @@ deploy: all
 	cp *.html prog_seq_c_cours
 
 clean:
-	rm -f *.pdf *.html *.markdown
+	rm -f *.pdf *.html *.markdown yq_linux_amd64*