S = input()

for i in range(3, len(S)):
    for j in range(0, len(S)+1-i):
        subs = S[j:j+i]
        c = subs.find("c")
        w = subs.find("w")
        if c == -1 or w == -1:
            continue
        if c > w:
            continue
        if subs.count("w") >= 2:
            print(i)
            sys.exit(1)
print(-1)