"""
N = int(input())
l = []
for _ in range(N):
    r,R = map(int,input().split())
    l.append((R,r))
l.sort()
dp = [0] * N
m = [0] * N
dp[0] = 1
m[0] = 1
for i in range(1,N):
    R,r = l[i]
    start = 0
    if l[start][0] > r:
        dp[i] = 1
        m[i] = m[i-1]
    else:
        end = i
        while end - start > 1:
            mid = end + start >> 1
            if l[mid][0] <= r:
                start = mid
            else:
                end = mid
        dp[i] = m[start] + 1
        m[i] = max(dp[i],m[i-1])
print(N - m[-1])
"""
N = int(input())
l = []
q = []
for _ in range(N):
    r,R = map(int,input().split())
    l.append((R,r))
l.sort()
import heapq
ans = 0
for R,r in l:
    while q:
        RR,rr = heapq.heappop(q)
        if RR <= r:
            r = rr
            ans += 1
        else:
            heapq.heappush(q,(RR,rr))
            break
    heapq.heappush(q,(R,r))
print(N - 1 - ans)