start = 0
result = 100

input_str = raw_input('')

def search_cww(string, start):
    cww_str = "cww"

    cww_cnt = 0
    str_cnt = 0
    for i in range(start, len(string)):
        if string[i] == cww_str[cww_cnt]: 
            if cww_cnt == 0:
                c_position = i

            str_cnt += 1
#            print("cww_cnt", cww_cnt)
#            print("str_cnt", str_cnt)
            if cww_cnt >= 2:
                return c_position, str_cnt
            cww_cnt += 1
        else:
            if cww_cnt > 0:
                str_cnt += 1
    return -1, -1

while True:
    start, cnt = search_cww(input_str, start)
#    print("start:", start)
#    print("cnt:", cnt)
    start += 1
    if cnt < 0:
        break
    else:
        if result > cnt:
            result = cnt

if result == 100:
    print(-1)
else:
    print(result)