def count_chiwawa(str):
    count_flg = False
    count = 0
    w_count = 0
    for s in list(str):
        if s == "c":
            count_flg = True
            w_count = 0
            count = 0
        elif s == "w" and count_flg:
            w_count += 1

        if count_flg:
            count += 1
        if w_count == 2:
            return count
    return -1
    
print(count_chiwawa(input()))