# A reducer for the word-count task that uses a fixed amount of memory.
# (This isn't quite true as ints in python can be arbitrarily large, but
# it it doubtful this program would ever use more than a few MBs of memory :) 

import sys

# These keep track of the last word we saw and how many times we've seen it
last_word = None
word_count = 0

for line in sys.stdin:
    parts = line.split()
    (word, c) = (parts[0], int(parts[1]))
    
    # We're on to a new word now, and it's not the first word
    if word != last_word and last_word is not None:
        print "%s\t%s" % (last_word, word_count)
        word_count = 0
    last_word = word
    word_count += c

# We have to print out the last key that we see, since it won't 
# get printed as we iterate over the lines of the file
print "%s\t%s" % (last_word, word_count)