count form also exists for paucal numbers (1.5, 2, 3 and 4); usually it coincides with genitive singular, but has notable exceptions with stressed endings: (2 hours), but (middle of an hour); (22 balls), but (volume of the ball); (3 rows/lines), but (step out of the line); (4 steps), but (half a step). (half an hour) is additional exception; other nouns with prefix does not have stressed ending.