I added node name aliases as comment to extracted netlist, and I have it:
* 124 = a[0] (6.4,16452.4)
* 124 = b[3] (1130.5,8134.5)
* 124 = cn (-65.8,-418)
* 124 = m (-107.3,-418)
* 124 = s[0] (1130.5,3136.5)
* 124 = U13/ix5651/A (5.8,16359.4)
* 124 = U13/ix5651/B (3.5,16359.4)
* 124 = U13/ix5651/C (8.1,16359.4)
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for other input signals like b[3],cn,m there are no transistors. I think all of them are supposed as a node a[0],because there are many transistors with a[0] signal. If your probability about floating terminals be correct, how can I simulate this netlist with HSPICE,because they are independent input signals and I want to simulate it with different values.