open System
open System.Text.RegularExpressions

let pattern = new Regex(@"c[^cw]*w[^cw]*w")
let searchCww str =
    pattern.Matches(str) |>
    function m when m.Count = 0 -> -1
           | m -> seq { for i in 0..(m.Count - 1) -> m.[i].Length} |> Seq.min

Console.ReadLine () |> searchCww |> printfn "%d"