Scanf.scanf "%d %d %d %d" (fun a b c d ->
    let calc combo a =
        let rec loop combo a =
            if combo >= 100 then loop (combo - 100) (a * 2)
                           else a
        in
        loop combo a
    in
    if d < 10 then (
        let rec loop combo great perfect score =
            if perfect = 0 then score else
            if great > 0 then loop (combo + 1) (great - 1) perfect (score + calc combo 50)
                         else loop (combo + 1) great (perfect - 1) (score + calc combo 100)
        in
        let sc = loop 0 b a 0 in
        Printf.printf "Possible\n%d\n" sc
    ) else print_endline "Impossible"
)