s = [
      [0, 0, 0, 1, 0]  #a1
      [0, 0, 1, 0, 0]  #a2
      [0, 0, 0, 0, 1]  #a0
    ]

s = [
    [0, 0, 0, 0, 1, 0]  #a1
    [0, 0, 0, 1, 0, 0]  #a2
    [0, 0, 0, 1, 0, 0]  #a2
    [1, 0, 0, 0, 0, 0]  #not taken
    [1, 0, 0, 0, 0, 0]  #not taken
  ]