cww_str = ['c',
           'w',
           'w']

input_str = raw_input()

cww_counter = 0
result = 0

for i in range(len(input_str)):
    if cww_str[cww_counter] == input_str[i]:
        cww_counter += 1
        if cww_counter == 3:
            result = i + 1 - input_str.index('c')
            break

if cww_counter == 3 :
    print(result)
else:
    print(-1)