fun readStr () =
    let
        fun scan reader stream = SOME (StringCvt.splitl (not o Char.isSpace) reader (StringCvt.skipWS reader stream))
    in
        valOf (TextIO.scanStream scan TextIO.stdIn)
    end


fun intString n =
    if 0 <= n
    then Int.toString n
    else "-" ^ Int.toString (abs n)


fun findAnsAux _ [] _ = NONE
  | findAnsAux i (#"c"::tl) acc = if acc = [] then findAnsAux (i + 1) tl [i]
                               else findAnsAux (i + 1) tl acc
  | findAnsAux i (#"w"::tl) acc = if acc = [] then findAnsAux (i + 1) tl []
                               else if List.length acc = 1 then findAnsAux (i + 1) tl (i::acc)
                               else if List.length acc = 2 then SOME (i - List.last acc + 1)
                               else findAnsAux (i + 1) tl acc
  | findAnsAux i (_::tl) acc = findAnsAux (i + 1) tl acc 

fun findAns [] NONE = ~1
  | findAns [] (SOME x) = x
  | findAns (h::tl) acc = 
    let
        val chiwawa = findAnsAux 0 (h::tl) []
    in
        case acc of
            NONE => findAns tl chiwawa
          | SOME accV => 
            case chiwawa of
                NONE => findAns tl acc
              | SOME chiwawaV => findAns tl (SOME (Int.min (accV, chiwawaV)))
    end



val () =
    let
        val s = readStr ()

        val ans = findAns (String.explode s) NONE
    in
        print (intString ans ^ "\n")
    end