diff --git a/Include/Python.h b/Include/Python.h
index 41d0eecccab..17765147bb0 100644
--- a/Include/Python.h
+++ b/Include/Python.h
@@ -122,7 +122,7 @@ PERFORMANCE OF THIS SOFTWARE.
 
 #include "pyfpe.h"
 
-/* These definitions much match corresponding definitions in graminit.h.
+/* These definitions must match corresponding definitions in graminit.h.
    There's code in compile.c that checks that they are the same. */
 #define Py_single_input 256
 #define Py_file_input 257