#!/usr/bin/env python3 
  
from operator import itemgetter 
import sys 
  
current_word = None
current_count = 0
word = None
  
# read the entire line from STDIN 
for line in sys.stdin: 
    # remove leading and trailing whitespace 
    line = line.strip() 
    # splitting the data on the basis of tab we have provided in mapper.py 
    word, count = line.split('\t', 1) 
    # convert count (currently a string) to int 
    try: 
        count = int(count) 
    except ValueError: 
        # count was not a number, so silently 
        # ignore/discard this line 
        continue
  
    # this IF-switch only works because Hadoop sorts map output 
    # by key (here: word) before it is passed to the reducer 
    if current_word == word: 
        current_count += count 
    else: 
        if current_word: 
            # write result to STDOUT 
            print( '%s\t%s' % (current_word, current_count) )
        current_count = count 
        current_word = word 
  
# do not forget to output the last word if needed! 
if current_word == word: 
    print( '%s\t%s' % (current_word, current_count) )