sss = list(input())
str_count = 0
str_count_start = False
w_count = 0
save_str_count = 999
for ss in range(len(sss)):
    for s in range(ss + 1,len(sss)):
        if w_count == 2:
            break
        elif sss[ss] == "c" and not str_count_start:
            str_count_start = True
        elif str_count_start and sss[s] == "w":
            w_count += 1
        if str_count_start:
            str_count += 1
    if save_str_count > str_count and w_count == 2:
        save_str_count = str_count
    w_count = 0
    str_count = 0
    str_count_start = False
if save_str_count == 999:
    print(-1)
else:
    print(save_str_count)