diff --git a/ipynb/DocstringFixpoint.ipynb b/ipynb/DocstringFixpoint.ipynb
index 2e0485a..7dd905f 100644
--- a/ipynb/DocstringFixpoint.ipynb
+++ b/ipynb/DocstringFixpoint.ipynb
@@ -29,7 +29,7 @@
     "of numbers representing daily rainfall amounts as entered by a user. The list may contain the number -999 ",
     "indicating the end of the data of interest. Produce ",
     "the average of the non-negative values in the list up to ",
-    "the first -999 (if it shows up).* \n",
+    "the first -999 (if it shows up). There may be negative numbers other than -999 in the list.* \n",
     "\n",
     "We start by writing a function prototype containing the complete problem statement as the docstring:"
    ]