#!/usr/bin/env python

import sys
from collections import defaultdict


def main():
  input = sys.argv[1]
  batch_number = sys.argv[2]
  mms = {}

  max_mmset_size = 0

  with open(input, 'r') as f:
    for l in f:
      mm, hostname = l.rstrip().split(' ')
      if mm not in mms:
        mms[mm] = []
      mms[mm].append(hostname)

  max_mmset_size = max([len(mms[x]) for x in mms])

  batches = {x: [] for x in range(0, max_mmset_size)}
  for i in range(0, max_mmset_size):
    for mm in mms:
      if len(mms[mm]) -1 >= i:
        batches[i].append(mms[mm][i])

  for h in batches[int(batch_number)]:
    print(h)


if __name__ == '__main__':
  main()