Saturdays at work

My institution, in its infinite wisdom, chooses to observe Independence Day.
And when July 4th falls on a day in the summer semester, to make up for the missed day, we have to teach on the following Saturday.
This year, our schedule has changed slightly, moving about a week later: consequently the 4th lay outside the semester completely.  And to compensate, they are making us work two saturdays to make up for it.

Yours, completely confused by this,
N.