Thirteen.

In case you were wondering.

And those were thirteen of those special Distribution Media Format floppies, which are specially formatted to hold more data than a normal 1.44MB floppy disc. The high-capacity floppies reduced the floppy count by two, which resulted in a tremendous savings in cost of manufacturing and shipping.

(I'm sure there are the conspiracy-minded folks who think that DMF was invented as an anti-piracy measure. It wasn't; it was a way to reduce the number of floppy disks. That the disks were difficult to copy was a side-effect, not a design goal.)

(For comparison, Windows 3.1 came on six floppies. Windows NT 3.1 came on twenty-two. And yesterday, one of my colleagues reminded me that Windows NT setup asked for the floppy disks out of order! I guess it never occurred to them that they could renumber the disks.)