valid_cusip = proc (s: string) returns (bool)
    own chars: string := "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ*@#"
    if string$size(s) ~= 9 then return(false) end
    sum: int := 0
    for i: int in int$from_to(1,8) do
        v: int := string$indexc(s[i], chars)-1
        if v<0 then return(false) end
        if i//2=0 then v := v*2 end
        sum := sum + v/10 + v//10
    end
    check: int := (10 - sum // 10) // 10
    return(check = string$indexc(s[9], chars)-1)
end valid_cusip

start_up = proc ()
    po: stream := stream$primary_output()
    cusips: array[string] := array[string]$[
        "037833100",
        "17275R102",
        "38259P508",
        "594918104",
        "68389X106",
        "68389X105"
    ]

    for cusip: string in array[string]$elements(cusips) do
        stream$puts(po, cusip || ": ")
        if valid_cusip(cusip)
            then stream$putl(po, "valid")
            else stream$putl(po, "invalid")
        end
    end
end start_up