Study=fail & not study=pass

1) Study=Pass.
2)Not Study=Fail.
adding 1 or 2.

3)Study+Not Study=Pass+Fail.
4)Pass=Not Fail.
5)Fail=Not Pass.
adding 4 or 5.

6)Study+Not Study=Not Fail+Fail.

7)STUDY=FAIL.
simple
not study=pass