text = input()
super_index = [i for i, c in enumerate(text) if c == 'c']
cww_len = []
for i in range(len(super_index)):
    cur_index = super_index[i] + 1
    w_count = 0
    while cur_index < len(text):
        if text[cur_index] == 'w':
            w_count += 1
        if w_count == 2:
            cww_len.append(cur_index - super_index[i] + 1)
            break
        cur_index += 1
        
if len(cww_len) == 0:
    print(-1)
else:
    print(min(cww_len))