S = input()

c_flg = False
finish_flg = False
w_count = 0
length = 0
for ch in S:

    if ch == "c":
        c_flg = True
        length = 1
        continue

    if c_flg:
        length += 1

        if ch == "w":
            w_count += 1

            if w_count == 2:
                finish_flg = True
                break

if finish_flg:
    print(length)
else:
    print(-1)