n = int(input())
p = []
left = []
right = []
for i in range(n):
l, r = map(int, input().split())
left.append(l)
right.append(r)
p.append((l, r))
p.sort()
start = p[0][1]
ans = 1
for i in range(1, n):
if start < p[i][0]:
start = p[i][1]
ans += 1
print(ans)