def main():
  mod = 998244353

  class FenwickTreeMod:
    def __init__(self, n):
      self.n = n
      self.data = [0] * (n + 1)
    def add(self, k, x):
      k += 1
      while k <= self.n:
        self.data[k] += x
        self.data[k] %= mod
        k += k & -k
    def sum(self, k):
      res = 0
      while k:
        res += self.data[k]
        res %= mod
        k -= k & -k
      return res

  def compress(a):
    mem = {}
    for idx, elm in enumerate(sorted(set(a))):
      mem[elm] = idx
    return mem

  N = int(input())
  points = [None] * N
  for i in range(N):
    a, b = map(int, input().split())
    points[i] = [a + b, a - b]
  if points[0][0] > points[-1][0]:
    for i in range(N):
      points[i][0] *= -1
  if points[0][1] > points[-1][1]:
    for i in range(N):
      points[i][1] *= -1
  y = [i for i, j in points]
  mem = compress(y)
  for i in range(N):
    points[i][0] = mem[y[i]]
  points[1:-1] = sorted(points[1:-1])
  ft = FenwickTreeMod(len(mem))
  ft.add(0, 1)
  for i in range(1, N - 1):
    ft.add(points[i][1], ft.sum(points[i][1] + 1))
  print(ft.sum(points[-1][1] + 1))
main()