import sys
input = sys.stdin.readline

from operator import itemgetter

N=int(input())
AB=[list(map(int,input().split())) for i in range(N)]

AB.sort(key=itemgetter(1))

now=0
ANS=0
for a,b in AB:
    if now<=a:
        ANS+=1
        now=b

print(N-ANS)