string = input()
c_indices = [i for i, x in enumerate(string) if string[i] == "c"]
w_indices = [i for i, x in enumerate(string) if string[i] == "w"]

length = 1000

for c_index in c_indices:

    for i, w_index in enumerate(w_indices[:-1]):
        if c_index < w_index:
            ww_index = w_indices[i + 1]
            length = min(length, ww_index - c_index + 1)

if length == 1000:
    print(-1)
else:
    print(length)