S = input()
cww_col = ["c", "w", "w"]
check = []  # check == [[:now, :len], ... ,[]]
for Si in S:
    if Si == cww_col[0]:
        check.append([0, 0])
    for c in check:
        if c[0] < 2:
            if Si == cww_col[1]:
                c[0] += 1
            c[1] += 1

check =  sorted([c for c in check if c[0] == 2], key=lambda x:x[1])
if len(check) == 0:
    print(-1)
else:
    print(check[0][1])