def count_chiwawa(str):
    str_len = len(str)
    count = 0
    w_count = 0
    res = 999
    i = 0
    j = 0
    for i in range(str_len):
        if str[i] == "c":
            j = i + 1
            count = 1
            w_count = 0
            for k in range(j,str_len):
                count += 1
                if str[k] == "w":
                    w_count += 1
                if w_count == 2:
                    if count < res:
                        res = count
                    break
    if res == 999:
        return -1
    else:
        return res
print(count_chiwawa(input()))