n=int(input())
a=sorted([list(map(int,input().split())) for i in range(n)],key=lambda item: (item[0], -item[1]))
c=0
T=True
for i in range(n-1):
	if a[i][1]>a[i+1][0]:
		if T and i!=n-2 and a[i][1]<a[i+2][0]:
			T=False
			continue
		c+=1 
		T=True
print(c)