grammar fix
diff --git a/Doc/lib/librunpy.tex b/Doc/lib/librunpy.tex
index 4be9901..c7a7e51 100644
--- a/Doc/lib/librunpy.tex
+++ b/Doc/lib/librunpy.tex
@@ -10,7 +10,7 @@
\versionadded{2.5}
The \module{runpy} module is used to locate and run Python modules
-without importing them first. It's main use is to implement the
+without importing them first. Its main use is to implement the
\programopt{-m} command line switch that allows scripts to be located
using the Python module namespace rather than the filesystem.