1 > 0

2>1, 3>2, 4>3, 5>4, 6>5, 7>6, 8>7, 9>8, 10>9, 11>10, 12>11, 13>12, 14>13, 15>14, 16>15, 17>16, 18>17, 19>18

16>19, 17>16, 18>17, 19>18

16>19, 17>16, 14>17, 15>14, 12>15, 13>12, 10>13, 11>10, 8>11, 9>8, 6>9, 7>6, 4>7, 5>4, 2>5, 3>2, 0>3