from enum import Enum, auto


def accum_dp(xs: list, f, op, e, init: dict):
    dp = init.copy()
    for x in xs:
        pp = {}
        dp, pp = pp, dp
        for fm_key, fm_val in pp.items():
            for to_key, to_val in f(fm_key, fm_val, x):
                dp[to_key] = op(dp.get(to_key, e), to_val)

    return dp


class E(Enum):
    S = auto()
    C = auto()
    W1 = auto()
    W2 = auto()


def f(k, v, x):
    # k : (最後に選択した E, E.C からの長さ)
    state, w = k

    if state == E.S:
        yield k, v

    match (state, x):
        case (E.S, 'c'):
            yield (E.C, 1), v

        case (E.C, 'w'):
            yield (E.W1, w+1), v

        case (E.W1, 'w'):
            yield (E.W2, 0), w+1

        case (E.W2, _):  # goal
            yield (E.W2, 0), v

        case _:  # 現在の状態を維持
            yield (state, w+1), v


INF = 1 << 62
S = input()

init = {(E.S, 0): 0}
dp = accum_dp(S, f, min, INF, init)

ans = INF
for (st, _), v in dp.items():
    if st == E.W2:
        ans = min(ans, v)

if ans == INF:
    print(-1)
else:
    print(ans)