pk1,pk2,pk3,content
b,a,g,b-a-g
b,b,g,b-b-g
b,c,g,b-c-g
b,d,g,b-d-g
b,e,g,b-e-g
b,f,g,b-f-g
b,g,g,b-g-g
b,h,g,b-h-g
b,i,g,b-i-g
b,j,g,b-j-g
b,k,g,b-k-g
b,l,g,b-l-g
b,m,g,b-m-g