from mrjob.job import MRJob
import re

WORD_RE = re.compile(r"[\w']+")

class MRWordFreqCount(MRJob):
  
  def mapper(self, _, line):
    for word in WORD_RE.findall(line):
      yield word.lower(), 1

  def reducer(self, word, counts):
    yield word, sum(counts)

  def combiner(self, word, counts):
    yield word, sum(counts)

if __name__ == '__main__':
  MRWordFreqCount.run()