#1533486: fix types in refcount intro.
diff --git a/Doc/c-api/intro.rst b/Doc/c-api/intro.rst
index 5e9f525..9befaf7 100644
--- a/Doc/c-api/intro.rst
+++ b/Doc/c-api/intro.rst
@@ -137,7 +137,7 @@
object type, such as a list, as well as performing any additional finalization
that's needed. There's no chance that the reference count can overflow; at
least as many bits are used to hold the reference count as there are distinct
-memory locations in virtual memory (assuming ``sizeof(long) >= sizeof(char*)``).
+memory locations in virtual memory (assuming ``sizeof(Py_ssize_t) >= sizeof(void*)``).
Thus, the reference count increment is a simple operation.
It is not necessary to increment an object's reference count for every local