k proof-1
k proof-2
k proof-3
k proof-4
k proof-5
k proof-6
k proof-7
k proof-8
k proof-9
k proof-10
k proof-11
k proof-12
k proof-13
k proof-14
k proof-15
k proof-16
k proof-17
k proof-18
k proof-19
k proof-20
k proof-21
s proof-1
s proof-2
