local factor = "137137" local sum, code while true do local n, rest = io.read("*n", "*l") if n==nil then break end num = string.format("%06d",n) sum = 0 for i=1,6 do sum = sum + string.sub(factor,i,i) * string.sub(num,i,i) end sum = 10 - math.mod(sum,10) code = string.sub("ABCDEFGHIK",sum,sum) print(num.." "..code..rest) end