output_description: Print the maximum number of friendly pairs.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      a_1 b_1
      a_2 b_2
      :
      a_N b_N
      c_1 d_1
      c_2 d_2
      :
      c_N d_N
attempt: n = int(input())
  
  
  class Cumulative_Sum_2D:
      def __init__(self, a):
          lai = len(a)
          laj = len(a[0])
          self.s = [[0] * (laj + 1) for _ in range(lai + 1)]
          for i in range(lai):
              for j in range(laj):
                  self.s[i + 1][j + 1] = self.s[i + 1][j] + a[i][j]
          for i in range(lai):
              for j in range(laj):
                  self.s[i + 1][j + 1] += self.s[i][j + 1]
  
      def sum(self, li, lj, ri, rj):
          s = self.s
          return s[ri][rj] - s[li][rj] - s[ri][lj] + s[li][lj]
  
  
  size = 2 * n + 2
  ab = [[0] * size for _ in range(size)]
  cd = [[0] * size for _ in range(size)]
  ablist = []
  cdlist = []
  
  for _ in range(n):
      xi, yi = map(int, input().split())
      ab[xi][yi] += 1
      ablist.append((xi, yi))
  for _ in range(n):
      xi, yi = map(int, input().split())
      cd[xi][yi] += 1
      cdlist.append((xi, yi))
  csab = Cumulative_Sum_2D(ab)
  cscd = Cumulative_Sum_2D(cd)
  # import numpy as np
  # print(np.array(csab.s))
  # print(np.array(cscd.s))
  ans = 0
  """
  for ci,di in cdlist:
      if cscd.sum(0,0,ci+1,di+1) <= csab.sum(0,0,ci+1,di+1):
          ans += 1
      print(ci,di,cscd.sum(0,0,ci+1,di+1) ,csab.sum(0,0,ci+1,di+1))
  print(ans)
  """
  ans2 = 0
  for ai, bi in cdlist:
      if cscd.sum(ai, bi, size, size) == 0:
          ans2 += 1
      # print(ai,bi,cscd.sum(ai,bi, size, size) , csab.sum(ai,bi, size, size))
  
  print(n - ans2)
  
problem_description: Statement
  
  On a two-dimensional plane, there are N red points and N blue points. The
  coordinates of the i-th red point are (a_i, b_i), and the coordinates of the
  i-th blue point are (c_i, d_i).
  
  A red point and a blue point can form a _friendly pair_ when, the x-coordinate
  of the red point is smaller than that of the blue point, and the y-coordinate
  of the red point is also smaller than that of the blue point.
  
  At most how many friendly pairs can you form? Note that a point cannot belong
  to multiple pairs.
samples: [{"input": "3\n    2 0\n    3 1\n    1 3\n    4 2\n    0 4\n    5 5", "output": "2\n    \n\nFor example, you can pair (2, 0) and (4, 2), then (3, 1) and (5, 5).\n\n* * *"}, {"input": "3\n    0 0\n    1 1\n    5 2\n    2 3\n    3 4\n    4 5", "output": "2\n    \n\nFor example, you can pair (0, 0) and (2, 3), then (1, 1) and (3, 4).\n\n* * *"}, {"input": "2\n    2 2\n    3 3\n    0 0\n    1 1", "output": "0\n    \n\nIt is possible that no pair can be formed.\n\n* * *"}, {"input": "5\n    0 0\n    7 3\n    2 2\n    4 8\n    1 6\n    8 5\n    6 9\n    5 4\n    9 1\n    3 7", "output": "5\n    \n\n* * *"}, {"input": "5\n    0 0\n    1 1\n    5 5\n    6 6\n    7 7\n    2 2\n    3 3\n    4 4\n    8 8\n    9 9", "output": "4"}]