S = input()

min_length = 101
for i, ch in enumerate(S):

    if ch == 'c':

        w_length = 0
        word_length = 1
        finish_flg = False
        for j in range(i+1, len(S)):

            word_length += 1
            if S[j] == 'w':

                w_length += 1
                if w_length == 1:
                    continue
                else:
                    finish_flg = True
                    break

        if finish_flg:
            min_length = min(min_length, word_length)

if min_length == 101:
    print(-1)
else:
    print(min_length)