When one of the rowers is two cities: C (3,2) * C (4,1) * C (7,3) = 420.
There are two kinds of cities rowing right oars: C(3,1) * c (4,2) * c (6,3) = 360.
When all right oars are two kinds of cities: c (4,3) * c (5,3) = 40 kinds.
* * * 336+420+360+40 =1156 species.