{
  "<pad>": 0,
  "<+>": 1,
  "<->": 2,
  "<0>": 3,
  "<1>": 4,
  "<2>": 5,
  "<3>": 6,
  "<4>": 7,
  "<5>": 8,
  "<6>": 9,
  "<7>": 10,
  "<8>": 11,
  "<9>": 12
}