line-mode
words
        ascii-digits
        uppercase-alphabet
        catenate #(list+list)
        save-a
        index
    m5
    10
    base #(list to num)
m4
sum
itemize
        dec
        10
        divmod
        inc
    m4
    0
    diff #(list-elem)
b4
3
times #(eval)
push-a
select