from itertools import chain
import sys
import os
import inspect
from operator import itemgetter
input = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 7)

if os.getenv("TKTKLOCAL", False):
    def debug(*arg, sep=" ", end="\n"):
        print(*arg, sep=sep, end=end, file=sys.stderr)

    def debug_indent(*arg, sep=" ", end="\n", indent="    "):
        frame = inspect.currentframe().f_back
        par_func = inspect.getframeinfo(frame).function
        if par_func == "<module>":
            debug(*arg, sep=sep, end=end)
            return

        frame_stack = inspect.stack()
        if len(frame_stack) > 30:
            return

        depth = sum(f.function == par_func for f in frame_stack)
        debug(indent * (depth - 1), end="")
        debug(*arg, sep=sep, end=end)
else:
    def debug(*arg, **kwarg):
        pass

    def debug_indent(*arg, **kwarg):
        pass


class FenwickTree(object):
    def __init__(self, n):
        self.n = n
        self.log = n.bit_length()
        self.data = [0] * n

    def _sum(self, r):
        s = 0
        while r > 0:
            s += self.data[r - 1]
            r -= r & -r
        return s

    def add(self, p, x):
        """ a[p] += xを行う"""
        p += 1
        while p <= self.n:
            self.data[p - 1] += x
            p += p & -p

    def sum(self, l, r):
        """a[l] + a[l+1] + .. + a[r-1]を返す"""
        return self._sum(r) - self._sum(l)

    def lower_bound(self, x):
        """a[0] + a[1] + .. a[i] >= x となる最小のiを返す"""
        if x <= 0:
            return -1
        i = 0
        k = 1 << self.log
        while k:
            if i + k <= self.n and self.data[i + k - 1] < x:
                x -= self.data[i + k - 1]
                i += k
            k >>= 1
        return i

    def __repr__(self):
        res = [self.sum(i, i+1) for i in range(self.n)]
        return " ".join(map(str, res))



def main():
    N = int(input())
    M = list(tuple(map(int, input().split())) for _ in range(N))
    M.sort(key=itemgetter(1, 0))

    R = sorted(set(chain(*M)))
    rtoi = {r: i for i, r in enumerate(R)}
    bit = FenwickTree(len(rtoi) + 5)

    cnt = 0
    for s, t in M:
        s = rtoi[s]
        t = rtoi[t]

        f = bit.sum(0, s+1)
        if f == 0:
            cnt += 1
            bit.add(t, 1)
        else:
            i = bit.lower_bound(f)
            bit.add(i, -1)
            bit.add(t, 1)
    print(cnt - 1)

    
main()