diff --git a/prog-strings.Rmd b/prog-strings.Rmd
index c8c0773..266abc3 100644
--- a/prog-strings.Rmd
+++ b/prog-strings.Rmd
@@ -1,4 +1,4 @@
-## Programming with strings
+# Programming with strings
 
 ```{r}
 library(stringr)