import itertools

s = input()
u = list(zip(s, range(len(s))))
ls = [z - x + 1 for (a, x), (b, y), (c, z) in itertools.product(u, repeat = 3) if (a == 'c' and b == c == 'w' and x < y < z)]

if len(ls) == 0:
    print(-1)
else:
    print(min(ls))