a_2 a_1 a_5 b_4 b_2 b_1 b_3 c_2 c_3 b_9 b_8 b_7 c_4 c_1 c_13 c_5 c_6 c_7 c_12 c_8 c_9 c_10 c_11 d_1 d_2 d_3 d_4 d_5 d_6 d_7 d_8 d_9 d_10 d_11 d_12 d_13 d_14 d_15 d_16