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: def popcount(n):
  	res=0
  	while n > 0:
  		res += n%2;
  		n /= 2
  	return res
  n=0
  def init_seg(_n):
  	n=1
  	while(n < _n) n *= 2
  
  data=[0]*n
  datb=[0]*n
  
  def add(a,b,x,k,l,r):
  	if a <=l and r <= b:
  		data[k] += x
  	else:
  		datb[k] += (min(b,r) - max(a,l))*x
  		add(a,b,x,2*k+1,l,(l+r)/2)
  		add(a,b,x,2*k+2,(l+r)/2,r)
  
  def sum(a,b,k,l,r):
  	if b <=l or r <=a:
  		return 0
  	elif a <= l and r <= b:
  		return data[k] * (r - l) + datb[k]
  	else:
  		res=(min(b,r) - max(a,l)) * data[k]
  		res+=sum(a,b,2*k+1,l,(l+r)/2)
  		res+=sum(a,b,2*k+2,(l+r)/2,r)
  		return res
  
  init_seg(1e5)
  for i in range(n):
  	add(i,i+1,0,0,0,n)
  
  N,C=map(int,input().split())
  for i in range(N):
  	s,t,c=map(int,input().split())
  	add(s,t,2**(c-1),0,0,n)
  
  res=0
  for i in range(1:1e5):
  	prev=sum(i-1,i,0,0,n)
  	curr=sum(i,i+1,0,0,n)
  	if prev == curr:
  		res = max(res, popcount(curr))
  	else:
  		res = max(res, popcount(curr | prev))
  
  print(res)
  
  
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"}]