[-1, -1, -1, 1, 1]
-1
[-1, -1, -1, 1]
[1, 1, 1, 1]
[-1, -1, -1, -1]
0
[-1, 1, 1, 1, 1]
  ***   at top-level: nfeltsign(nf,a,3)
  ***                 ^-----------------
  *** nfeltsign: domain error in nfeltsign: index > 2
  ***   at top-level: nfeltsign(nf,a,[-1..1])
  ***                 ^-----------------------
  *** nfeltsign: domain error in nfeltsign: index <= 0
  ***   at top-level: nfeltsign(nf,a,[1..3])
  ***                 ^----------------------
  *** nfeltsign: domain error in nfeltsign: index > 2
Total time spent: 4
