S = input()

cww_seq = []
for i in range(len(S)):
    if S[i] != "c":
        continue
    for j in range(i + 1, len(S)):
        if S[j] != "w":
            continue
        for k in range(j + 1, len(S)):
            if S[k] == "w":
                cww_seq.append(S[i: k+1])

if len(cww_seq) == 0:
    print(-1)
else:
    print(len(min(cww_seq, key=len)))