S = input()
c_w_w =[]
for i in range(len(S)):
    if S[i] == "c" and len(c_w_w) == 0:
        c_w_w.append(i)
    if S[i] == "w" and (len(c_w_w) == 1 or len(c_w_w) ==2):
        c_w_w.append(i)

if len(c_w_w) == 3:
    print(c_w_w[2] - c_w_w[0] + 1)
else:
    print(-1)