def _ceil_pow2(n: int) -> int: x = 0 while (1 << x) < n: x += 1 return x def _bsf(n: int) -> int: x = 0 while n % 2 == 0: x += 1 n //= 2 return x import typing class SegTree: def __init__(self, op: typing.Callable[[typing.Any, typing.Any], typing.Any], e: typing.Any, v: typing.Union[int, typing.List[typing.Any]]) -> None: self._op = op self._e = e if isinstance(v, int): v = [e] * v self._n = len(v) self._log = _ceil_pow2(self._n) self._size = 1 << self._log self._d = [e] * (2 * self._size) for i in range(self._n): self._d[self._size + i] = v[i] for i in range(self._size - 1, 0, -1): self._update(i) def set(self, p: int, x: typing.Any) -> None: assert 0 <= p < self._n p += self._size self._d[p] = x for i in range(1, self._log + 1): self._update(p >> i) def get(self, p: int) -> typing.Any: assert 0 <= p < self._n return self._d[p + self._size] def prod(self, left: int, right: int) -> typing.Any: assert 0 <= left <= right <= self._n sml = self._e smr = self._e left += self._size right += self._size while left < right: if left & 1: sml = self._op(sml, self._d[left]) left += 1 if right & 1: right -= 1 smr = self._op(self._d[right], smr) left >>= 1 right >>= 1 return self._op(sml, smr) def all_prod(self) -> typing.Any: return self._d[1] def max_right(self, left: int, f: typing.Callable[[typing.Any], bool]) -> int: assert 0 <= left <= self._n assert f(self._e) if left == self._n: return self._n left += self._size sm = self._e first = True while first or (left & -left) != left: first = False while left % 2 == 0: left >>= 1 if not f(self._op(sm, self._d[left])): while left < self._size: left *= 2 if f(self._op(sm, self._d[left])): sm = self._op(sm, self._d[left]) left += 1 return left - self._size sm = self._op(sm, self._d[left]) left += 1 return self._n def min_left(self, right: int, f: typing.Callable[[typing.Any], bool]) -> int: assert 0 <= right <= self._n assert f(self._e) if right == 0: return 0 right += self._size sm = self._e first = True while first or (right & -right) != right: first = False right -= 1 while right > 1 and right % 2: right >>= 1 if not f(self._op(self._d[right], sm)): while right < self._size: right = 2 * right + 1 if f(self._op(self._d[right], sm)): sm = self._op(self._d[right], sm) right -= 1 return right + 1 - self._size sm = self._op(self._d[right], sm) return 0 def _update(self, k: int) -> None: self._d[k] = self._op(self._d[2 * k], self._d[2 * k + 1]) n = int(input()) lr = [] s = {-10**9} for i in range(n): l, r = map(int, input().split()) lr.append((r, l)) s.add(l) s.add(r) lr.sort() s = sorted(list(s)) d = {x: i for i, x in enumerate(s)} m = len(s) st = SegTree(max,0, [0] * m) st.set(0, 0) for r, l in lr: R = d[r] L = d[l] res = st.prod(0, L+1) + 1 st.set(R, res) print(n-st.all_prod())