$$f1
 $$f1-2
 $$f1-3
 $$f1-4
 $$f10
 $$f10-11
 $$f10-12
 $$f11
 $$f11
 $$f11-12
 $$f11-14
 $$f12
 $$f13
 $$f13-14
 $$f14
 $$f15
 $$f15-16
 $$f16
 $$f17-18
 $$f19
 $$f19-20
 $$f19-21
 $$f2
 $$f2-3
 $$f20
 $$f20-22
 $$f21
 $$f24
 $$f25
 $$f26
 $$f27
 $$f28
 $$f3
 $$f3-4
 $$f4
 $$f4-5
 $$f45
 $$f48
 $$f49
 $$f5
 $$f5-6
 $$f51
 $$f537-543
 $$f6
 $$f6-7
 $$f7
 $$f7-8
 $$f7-9
 $$f8
 $$f8-9
 $$f9
 $$f9-10