diff --git a/addOK b/addOK
new file mode 100644
index 0000000..ac34c71
--- /dev/null
+++ b/addOK
@@ -0,0 +1,3 @@
+int addOK(int x, int y){
+    return !(~((x >> 31) ^ (y >> 31)) & ((x >> 31) ^ ((x  + y) >> 31)));
+}