output_description: Print the ID numbers for all the cities, in ascending order of indices (City
  1, City 2, ...).
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N M
      P_1 Y_1
      :
      P_M Y_M
attempt: n, m = map(int, input().split())
  i_p_y_pairs = [tuple(map(int, (("%d " % i) + input()).split())) for i in range(m)]
  i_p_y_pairs.sort(key=(lambda i_p_y: i_p_y[2]))
  
  ret = []
  current_p_idx = 0
  current_p = i_p_y_pairs[current_p_idx][1]
  for idx in range(m):
      p = i_p_y_pairs[idx][1]
      if p != current_p:
          current_ipy_pairs = i_p_y_pairs[current_p_idx:idx]
          current_ipy_pairs.sort(key=lambda ipy: ipy[2])
          for _idx_, ipy in enumerate(current_ipy_pairs):
              ret.append((ipy[0], "%06d" % current_p + "%06d" % (_idx_ + 1)))
          current_p_idx = idx
          current_p = i_p_y_pairs[current_p_idx][1]
  else:
      current_ipy_pairs = i_p_y_pairs[current_p_idx:]
      current_ipy_pairs.sort(key=lambda ipy: ipy[2])
      for _idx_, ipy in enumerate(current_ipy_pairs):
          ret.append((ipy[0], ("%06d" % current_p + "%06d" % (_idx_ + 1))))
  
  ret.sort(key=lambda x: x[0])
  for r in ret:
      print(r[1])
  
problem_description: Statement
  
  In Republic of Atcoder, there are N prefectures, and a total of M cities that
  belong to those prefectures.
  
  City i is established in year Y_i and belongs to Prefecture P_i.
  
  You can assume that there are no multiple cities that are established in the
  same year.
  
  It is decided to allocate a 12-digit ID number to each city.
  
  If City i is the x-th established city among the cities that belong to
  Prefecture i, the first six digits of the ID number of City i is P_i, and the
  last six digits of the ID number is x.
  
  Here, if P_i or x (or both) has less than six digits, zeros are added to the
  left until it has six digits.
  
  Find the ID numbers for all the cities.
  
  Note that there can be a prefecture with no cities.
samples: [{"input": "2 3\n    1 32\n    2 63\n    1 12", "output": "000001000002\n    000002000001\n    000001000001\n    \n\n  * As City 1 is the second established city among the cities that belong to Prefecture 1, its ID number is 000001000002.\n  * As City 2 is the first established city among the cities that belong to Prefecture 2, its ID number is 000002000001.\n  * As City 3 is the first established city among the cities that belong to Prefecture 1, its ID number is 000001000001.\n\n* * *"}, {"input": "2 3\n    2 55\n    2 77\n    2 99", "output": "000002000001\n    000002000002\n    000002000003"}]