Revert 42400.
diff --git a/Objects/listobject.c b/Objects/listobject.c
index a970c14..c083ffc 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2600,8 +2600,8 @@
 			if (PySequence_Fast_GET_SIZE(seq) != slicelength) {
 				PyErr_Format(PyExc_ValueError,
             "attempt to assign sequence of size %zd to extended slice of size %zd",
-					     (long)PySequence_Fast_GET_SIZE(seq),
-					     (long)slicelength);
+					     PySequence_Fast_GET_SIZE(seq),
+					     slicelength);
 				Py_DECREF(seq);
 				return -1;
 			}