# Introduction

Every month, your partner meets up with their best friend.
Both of them have very busy schedules, making it challenging to find a suitable date!
Given your own busy schedule, your partner always double-checks potential meetup dates with you:

- "Can I meet up on the first Friday of next month?"
- "What about the third Wednesday?"
- "Maybe the last Sunday?"

In this month's call, your partner asked you this question:

- "I'd like to meet up on the teenth Thursday; is that okay?"

Confused, you ask what a "teenth" day is.
Your partner explains that a teenth day, a concept they made up, refers to the days in a month that end in '-teenth':

- 13th (thirteenth)
- 14th (fourteenth)
- 15th (fifteenth)
- 16th (sixteenth)
- 17th (seventeenth)
- 18th (eighteenth)
- 19th (nineteenth)

As there are also seven weekdays, it is guaranteed that each day of the week has _exactly one_ teenth day each month.

Now that you understand the concept of a teenth day, you check your calendar.
You don't have anything planned on the teenth Thursday, so you happily confirm the date with your partner.
