from collections.abc import Iterable
from enum import IntEnum, auto
from functools import cache


class E(IntEnum):
    S = 0
    C = auto()
    W1 = auto()
    W2 = auto()

    def nexts(self):
        match self:
            case E.S: return [E.C]
            case E.C: return [E.W1]
            case E.W1: return [E.W2]
            case E.W2: return []

        assert False

    @staticmethod
    @cache
    def states():
        res = []
        for fm in E:
            for to in fm.nexts():
                res.append((fm, to))

        return res


def state_dp(xs: Iterable, op, e, init: dict, *, is_reset=True):
    dp = [e] * len(E)
    for k, v in init.items():
        dp[k] = v

    for x in xs:
        pp = [e] * len(E) if is_reset else dp.copy()
        dp, pp = pp, dp
        for fm, to in E.states():
            if not is_valid(to, pp[fm], x): continue
            dp[to] = op(to, dp[to], fm, pp[fm], x)

    return dp


def is_valid(to: E, fm_v, v) -> bool:
    if fm_v == (INF, INF): return False

    return True


def op(to: E, to_v, fm: E, fm_v, iv):
    res = (INF, INF)
    d, p = fm_v[0], -fm_v[1]  # (距離, 文字インデックス)
    i, v = iv
    match to:
        case E.C if v == 'c':
            res = min(res, (0, -i))
        case E.W1 | E.W2 if v == 'w':
            res = min(res, (d+(i-p), -i))

    return min(to_v, res)


INF = 1 << 60
S = input()

dp = state_dp(enumerate(S), op, (INF, INF), {E.S: (0, 0)}, is_reset=False)
ans, _ = dp[E.W2]
if ans == INF:
    print(-1)
else:
    print(ans+1)