1_1 1_2 1_3 2_1 2_2 3_1 3_2 3_3 3_4 4_1 4_2 4_3 4_4 4_5 4_6 5_1 5_10 5_2 5_3 5_4 5_5 5_6 5_7 5_8 5_9 6_1 6_2 6_3 7_1 7_2 7_3 7_4 7_5 8_1 8_2 9_1 9_2