S = input()
w_1_idx = S.find("w")
c_idx = S.rfind("c", w_1_idx)
w_2_idx = S.find("w", w_1_idx+1)
if c_idx != -1 and w_1_idx != -1 and w_2_idx != -1:
    print(w_2_idx-c_idx+1)

else :
    print(-1)