output_description: When the minimum required number of recorders is x, print the value of x.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N C
      s_1 t_1 c_1
      :
      s_N t_N c_N
attempt: n,c = map(int,input().split())
  stc = [[int(i) for i in input().split()] for j in range(n)]
  
  ans = 0
  
  stc.sort(key=lambda x:(x[2],x[1],x[0]))
  
  time = 10**5+1
  
  c_imos = [[0 for i in range(time)] for j in range(c)]
  
  for i in range(n):
      c_imos[stc[i][2]-1][stc[i][0]-1] += 1
      c_imos[stc[i][2]-1][stc[i][1]] -= 1
  
  #print(c_imos)
  
  nd_v = [[0 for i in range(time)] for j in range(c)]
  
  for i in range(c):
      for j in range(time):
          if j == 0:
              if c_imos[i][j] == 1:
                  nd_v[i][j] = 1
          else:q
              nd_v[i][j] = max(0,min(1,nd_v[i][j-1] + c_imos[i][j]))
  #print(nd_v)
  
  ans = 1
  
  for i in range(time-1):
      tmp = 0
      for j in range(c):
          tmp += nd_v[j][i]
      ans = max(tmp,ans)
  
  print(ans)
  
  exit()
      
  c_num = stc[0][2]
  t_num = stc[0][1]
  idx = 0
  print(stc)
  for i in range(1,n):
      print(t_num,i)
      if stc[idx+i][2] == c_num:
          if stc[idx+i][0] == t_num:
              stc[idx+i-1][1] = stc[idx+i][1]
              t_num = stc[idx+i][1]
              del stc[idx+i]
              idx -= 1
          else:
              print(t_num,t_num,t_num)
              c_num = stc[idx+i][2]
              t_num = stc[idx+i][1]
  
  stc.sort(key=lambda x:x[1])
  print(stc)
  exit()
  tmp = stc[0][1]
  
  ans = 1
  ans_tmp = 1
  
  for i in range(1,len(stc)):
      for j in range(i+1,len(stc)):
          if tmp >= stc[j][0]:
              ans_tmp += 1
          else:
              tmp = stc[j][0]
              ans = max(ans_tmp,ans)
problem_description: Statement
  
  Joisino is planning to record N TV programs with recorders.
  
  The TV can receive C channels numbered 1 through C.
  
  The i-th program that she wants to record will be broadcast from time s_i to
  time t_i (including time s_i but not t_i) on Channel c_i.
  
  Here, there will never be more than one program that are broadcast on the same
  channel at the same time.
  
  When the recorder is recording a channel from time S to time T (including time
  S but not T), it cannot record other channels from time S-0.5 to time T
  (including time S-0.5 but not T).
  
  Find the minimum number of recorders required to record the channels so that
  all the N programs are completely recorded.
samples: [{"input": "3 2\n    1 7 2\n    7 8 1\n    8 12 1", "output": "2\n    \n\nTwo recorders can record all the programs, for example, as follows:\n\n  * With the first recorder, record Channel 2 from time 1 to time 7. The first program will be recorded. Note that this recorder will be unable to record other channels from time 0.5 to time 7.\n  * With the second recorder, record Channel 1 from time 7 to time 12. The second and third programs will be recorded. Note that this recorder will be unable to record other channels from time 6.5 to time 12.\n\n* * *"}, {"input": "3 4\n    1 3 2\n    3 4 4\n    1 4 3", "output": "3\n    \n\nThere may be a channel where there is no program to record.\n\n* * *"}, {"input": "9 4\n    56 60 4\n    33 37 2\n    89 90 3\n    32 43 1\n    67 68 3\n    49 51 3\n    31 32 3\n    70 71 1\n    11 12 3", "output": "2"}]