diff --git a/y2019/constants.cc b/y2019/constants.cc
index 0a56ca5..f86110c 100644
--- a/y2019/constants.cc
+++ b/y2019/constants.cc
@@ -1,7 +1,6 @@
 #include "y2019/constants.h"
 
-#include <inttypes.h>
-
+#include <cinttypes>
 #include <map>
 
 #if __has_feature(address_sanitizer)