Scanf.scanf "%s" (fun s ->
    let n = String.length s in
    let rec loop_i i acc =
        let rec loop_j j acc =
            let rec loop_k k acc =
                if k >= n then acc else
                    let acc = if s.[k] = 'w' then min acc (k - i + 1) else acc in
                    loop_k (k + 1) acc
            in
            if j >= n then acc else
                if s.[j] = 'w' then loop_j (j + 1) (loop_k (j + 1) acc)
                               else loop_j (j + 1) acc
        in
        if i >= n then acc else
            if s.[i] = 'c' then loop_i (i + 1) (loop_j (i + 1) acc)
                           else loop_i (i + 1) acc
    in
    let ans = loop_i 0 max_int in
    let ans = if ans = max_int then -1 else ans in
    Printf.printf "%d\n" ans
)