a = [] readlines.each do |i| ar = i.split(' ') if ar[0] t = 0 ar[0].split(',').each do |r| ar[1].insert(r.to_i+t, ' ') if ar[1] t=t+1 end ar[1] = ar[0] if !ar[1] else ar[1] = i.strip end a << ar[1] || '' end puts a.join("\n")