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):
    yield k, v+1

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

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

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

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


INF = 1 << 62
S = input()

init = {E.S: 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)