import sys
input = sys.stdin.readline
N = int(input())
mod = 998244353
a = []
for _ in range(N):
  x, y = map(int, input().split())
  a.append((x + y, x - y))
#print(a)

def compress(init_val):
  t = sorted(set(init_val))
  d = dict([[t[i], i] for i in range(len(t))])
  res = [0] * len(init_val)
  for i in range(len(init_val)): res[i] = d[init_val[i]]
  return res

def compress2(init_val):
  xs = compress([init_val[i][0] for i in range(len(init_val))])
  ys = compress([init_val[i][1] for i in range(len(init_val))])
  return [(xs[i], ys[i] + 1) for i in range(len(init_val))]

a = compress2(a)
s = min(a[0], a[-1])
t = max(a[0], a[-1])
a = sorted(a[1: -1])

class BIT:
  def __init__(self, n):
    self.n = n
    self.data = [0] * (n + 1)
    self.el = [0] * (n + 1)
  def sum(self, i):
    s = 0
    while i > 0:
      s += self.data[i]
      s %= mod
      i -= i & -i
    return s
  def add(self, i, x):
    self.el[i] += x
    self.el[i] %= mod
    while i <= self.n:
      self.data[i] += x
      self.data[i] %= mod
      i += i & -i
  def get(self, i, j = None):
    if j is None:
      return self.el[i]
    return (self.sum(j) - self.sum(i)) % mod
  def lowerbound(self, s):
    x = 0
    y = 0
    for i in range(self.n.bit_length(), -1, -1):
      k = x + (1 << i)
      if k <= self.n and (y + self.data[k] < s):
        y += self.data[k]
        x += 1 << i
    return x + 1

fwk = BIT(N)
fwk.add(s[1], 1)
#print(s, a, t)
if s[1] <= t[1]:
  for x, y in a:
    if x in range(s[0], t[0] + 1) and y in range(s[1], t[1] + 1):
      fwk.add(y, fwk.sum(y))
  print(fwk.sum(t[1]))
else:
  for x, y in a:
    if x in range(s[0], t[0] + 1) and y in range(t[1], s[1] + 1):
      fwk.add(y, fwk.get(y - 1, N))
  print(fwk.get(t[1] - 1, N))