import bisect

n = int(input())
ranges = []
for _ in range(n):
    l, r = map(int, input().split())
    ranges.append((l, r))

tails = []
for i in range(n):
    l, r = ranges[i]
    if not tails:
        tails.append(l)
        continue
    current_max = tails[-1]
    desired = max(l, current_max + 1)
    if desired <= r:
        tails.append(desired)
    else:
        pos = bisect.bisect_left(tails, l)
        best_k = pos - 1
        if best_k >= 0:
            desired = max(l, tails[best_k] + 1)
            if desired <= r:
                if best_k + 1 >= len(tails):
                    tails.append(desired)
                else:
                    if desired < tails[best_k + 1]:
                        tails[best_k + 1] = desired
            else:
                pos = bisect.bisect_left(tails, l)
                if pos < len(tails):
                    if tails[pos] >= l:
                        tails[pos] = l
                else:
                    tails.append(l)
        else:
            pos = bisect.bisect_left(tails, l)
            if pos < len(tails):
                if tails[pos] >= l:
                    tails[pos] = l
            else:
                tails.append(l)

print(len(tails))