1<doc> 2 <!-- at least one present --> 3 <z-o> 4 <b/> 5 </z-o> 6 <o-o> 7 <c/> 8 </o-o> 9 <z-u> 10 <d/> 11 </z-u> 12 <o-u> 13 <e/> 14 </o-u> 15 <z-3> 16 <f/> 17 </z-3> 18 <o-3> 19 <g/> 20 </o-3> 21 <!-- more than one present when allowed --> 22 <z-o> 23 <b/> 24 </z-o> 25 <o-o> 26 <c/> 27 </o-o> 28 <z-u> 29 <d/> 30 <d/> 31 <d/> 32 </z-u> 33 <o-u> 34 <e/> 35 <e/> 36 <e/> 37 </o-u> 38 <z-3> 39 <f/> 40 <f/> 41 <f/> 42 </z-3> 43 <o-3> 44 <g/> 45 <g/> 46 <g/> 47 </o-3> 48 <!-- min 0 are not present --> 49 <z-o/> 50 <o-o> 51 <c/> 52 </o-o> 53 <z-u/> 54 <o-u> 55 <e/> 56 </o-u> 57 <z-3/> 58 <o-3> 59 <g/> 60 </o-3> 61</doc> 62