str = input()

count = 0
cww = ""
valid = False
for s in str:
    count += 1
    if s == 'c':
        cww = s
        count = 1
    elif s == 'w':
        cww += s
        if cww == "cww":
            valid = True
            break
if valid:
    print(count)
else:
    print(-1)