PAD = '<pad>'
UNK = '<unk>'
SOS = '<sos>'
EOS = '<eos>'
SOD = '<sod>'
EOD = '<eod>'
SENTENCE_START = '<s>'
SENTENCE_END = '</s>'
NER_TO_IDX = {'LOCATION': 0, 'MISC': 1, 'ORGANIZATION': 2, 'PERSON': 3,  'O': 4}
POS_TO_IDX = {
    "NN": 0,
    "PRP$": 1,
    "WRB": 2,
    "LS": 3,
    "FW": 4,
    "VBG": 5,
    "PRP": 6,
    "WP": 7,
    "JJS": 8,
    "DT": 9,
    "JJR": 10,
    "RB": 11,
    "WDT": 12,
    "VBP": 13,
    "NNS": 14,
    "SYM": 15,
    "UH": 16,
    "TO": 17,
    "RP": 18,
    "POS": 19,
    "CC": 20,
    ".": 21,
    "MD": 22,
    "NNPS": 23,
    "WP$": 24,
    ":": 25,
    "NNP": 26,
    "CD": 27,
    "PDT": 28,
    "RBS": 29,
    "VBD": 30,
    "IN": 31,
    "VB": 32,
    "EX": 33,
    "JJ": 34,
    "VBN": 35,
    "RBR": 36,
    "VBZ": 37,
    ",": 38
}