diff --git a/20230516/sum.h b/20230516/sum.h
new file mode 100644
index 0000000000000000000000000000000000000000..caab5a23535ae62d7ea0c2db3dc2c94cac686812
--- /dev/null
+++ b/20230516/sum.h
@@ -0,0 +1 @@
+extern int sum (int a, int b);