n=int(input()) a=[[0 for j in range(2)] for i in range(n)] for i in range(n): a[i][0],a[i][1]=map(int,input().split()) for i in range(n-1): for j in range(n-i-1): if a[j][1]>a[j+1][1]: a[j][0],a[j+1][0]=a[j+1][0],a[j][0] a[j][1],a[j+1][1]=a[j+1][1],a[j][1] c=[] c.append(a[0][1]) k=0 for i in range(1,n): if a[i][0]>=c[k]: k+=1 c.append(a[i][1]) print(k+1)