diff --git a/y2019/vision/constants.h b/y2019/vision/constants.h
index 8510f4c..959f5b7 100644
--- a/y2019/vision/constants.h
+++ b/y2019/vision/constants.h
@@ -3,6 +3,7 @@
 
 #include <array>
 #include <cmath>
+#include <cstdint>
 #include <string>
 
 namespace y2019 {