S = input()

f = 0
st = -1
for i, s in enumerate(S):
    if f == 0 and s == 'c':
        f += 1
        st = i
    elif f == 1 and s == 'c':
        st = i
    elif f == 1 and s == 'w':
        f += 1
    elif f == 2 and s == 'w':
        print(i - st + 1)
        break
else:
    print(-1)