import io
import sys
from collections import defaultdict, deque, Counter
from itertools import permutations, combinations, accumulate
from heapq import heappush, heappop
from bisect import bisect_right, bisect_left
from math import gcd
import math

_INPUT = """\
6
3
1 2
2 3
1 3
4
6 28
2 6
82 86
62 66
5
6 28
6 28
6 28
6 28
6 28
"""

def input():
  return sys.stdin.readline()[:-1]

def solve(test):
  N=int(input())
  M=[list(map(int, input().split())) for _ in range(N)]
  used1=[0]*N
  used2=[0]*N
  a=sorted([(M[i][0],i) for i in range(N)])
  b=sorted([(M[i][1],i) for i in range(N)])
  ans=N-1
  while a:
    r,i=a.pop()
    if used1[i]: continue
    used1[i]=1
    while b:
      R,j=b.pop()
      if used2[j]: continue
      if R<=r:
        used2[j]=1
        ans-=1
        break
  print(ans)

def random_input():
  from random import randint,shuffle
  N=randint(1,10)
  M=randint(1,N)
  A=list(range(1,M+1))+[randint(1,M) for _ in range(N-M)]
  shuffle(A)
  return (" ".join(map(str, [N,M]))+"\n"+" ".join(map(str, A))+"\n")*3

def simple_solve():
  return []

def main(test):
  if test==0:
    solve(0)
  elif test==1:
    sys.stdin = io.StringIO(_INPUT)
    case_no=int(input())
    for _ in range(case_no):
      solve(0)
  else:
    for i in range(1000):
      sys.stdin = io.StringIO(random_input())
      x=solve(1)
      y=simple_solve()
      if x!=y:
        print(i,x,y)
        print(*[line for line in sys.stdin],sep='')
        break

#0:提出用、1:与えられたテスト用、2:ストレステスト用
main(0)