(1)
"": 1 - - 2 - \\\\... 7 - : 8 - -: : 1 9 - \\\\ 10 - \\\\ 11 - - \\\\... 18 - 10 40- 19 - 20 - -2 20 - )))
"": 1 - \\\\ 2 - 3 - 4 - ...