n=int(input())
a=[[0 for i in range(2)] for j in range(n)]
for i in range(n):
    sr=input().split()
    a[i][0]=int(sr[0])
    a[i][1]=int(sr[1])
for i in range(n-1):
    for j in range(n-i-1):
        if(a[j][1]>a[j+1][1]):
            t=a[j][0]
            a[j][0]=a[j+1][0]
            a[j+1][0]=t
            t=a[j][1]
            a[j][1]=a[j+1][1]
            a[j+1][1]=t
c=[]
c.append(a[0][1])
k=0
for i in range(1,n):
    if(a[i][0]>=c[k]):
        k=k+1
        c.append(a[i][1])
print(k+1)
/**************************************************************
	Problem: 1372
	User: admin
	Language: Python
	Result: Accepted
	Time:92 ms
	Memory:34480 kb
****************************************************************/