3 sub { rec('200','a') . ' ' . rec('200','b') },
5 sub { rec('245','a') },
8 sub { rec('200','a') . ' ' . rec('200','b') },
10 sub { rec('245','a') },
13 sub { rec('200','a') . ' ' . rec('200','b') },
15 sub { rec('245','a') },
20 sub { rec('900','x') },