INF = float("inf")
s = input()
c = s.find("c")
ans = INF
while c != -1:
    w1 = s.find("w", c + 1)
    if w1 == -1:
        break
    w2 = s.find("w", w1 + 1)
    if w2 == -1:
        break
    ans = min(ans, w2 - c + 1)
    c = s.find("c", c + 1)
print(ans if ans != INF else -1)