1 z 2 \c 3 \c2 4 C 5 C2 6 x 7 x1 8 x1z 9 u 10 uz 11 u1 12 u1z 13 u12 14 u12z 15 u123 16 u123z 17 x{z 18 x{1z 19 x{1,z 20 x{1,2z 21 x{10000,20000z 22 23 24 null 25 ] 26 { 27 } 28 z 29 c 30 null 31 x 32 x 33 x 34 u 35 u 36 u 37 u 38 u 39 u 40 u 41 u 42 null 43 null 44 B 45 null