diff --git a/foundations/14_fibonacci/README.md b/foundations/14_fibonacci/README.md
index b56740b1822..78298992e1e 100644
--- a/foundations/14_fibonacci/README.md
+++ b/foundations/14_fibonacci/README.md
@@ -7,4 +7,5 @@ In this exercise, the Fibonacci sequence used is 1, 1, 2, 3, 5, 8, etc. (i.e. st
 ```javascript
 fibonacci(4); // returns the 4th member of the series: 3  (1, 1, 2, 3)
 fibonacci(6); // returns 8
+fibonacci(-1); // returns "OOPS"
 ```