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