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

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