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