One day Professor Frink meets the Tiger and the Elephant in the Forest of brain teasers.
he knows that
* The Tiger lies on Mondays, Tuesdays, and Wednesdays, and tells the truth on the other days of the week.
* The Elephant, on the other hand, lies on Thursdays, Fridays, and Saturdays, but tells the truth on the other days of the week.
Now they make the following statements to Professor Frink:
Tiger: Yesterday was one of my lying days.
Elephant: Yesterday was one of my lying days too.
What day is it?