pk1,pk2,pk3,content
a,l,a,a-l-a
a,l,b,a-l-b
a,l,c,a-l-c
a,l,d,a-l-d
a,l,e,a-l-e
a,l,f,a-l-f
a,l,g,a-l-g
a,l,h,a-l-h
a,l,i,a-l-i
a,l,j,a-l-j
a,l,k,a-l-k
a,l,l,a-l-l
a,l,m,a-l-m
a,l,n,a-l-n
a,l,o,a-l-o
a,l,p,a-l-p
a,l,q,a-l-q
a,l,r,a-l-r
a,l,s,a-l-s
a,l,t,a-l-t
a,l,u,a-l-u
a,l,v,a-l-v
a,l,w,a-l-w
a,l,x,a-l-x
a,l,y,a-l-y
a,l,z,a-l-z