0 _{1 _{2 3 4 5 _{6 7 8 _{9 10 11 12 13}} 14 15 16} 17 18 _{19 20 21 _{22 23 24} 25 26 27 _{28 _{29 30 31} 32 33 34 _{35 36}} 37 38 39} 40 41 42 43 44 _{45 46 47 {48 \atop 49}} 50}

1