def main():
  mod = 998244353

  # mod 998244353のFenwickTree
  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

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

  # 入力
  N = int(input())
  X, Y = [None] * N, [None] * N
  for i in range(N):
    a, b = map(int, input().split())
    X[i], Y[i] = a + b, a - b

  # 座標を反転しておく
  if X[0] > X[-1]:
    for i in range(N):
      X[i] = -X[i]
  if Y[0] > Y[-1]:
    for i in range(N):
      Y[i] = -Y[i]
  
  # y座標を圧縮
  mem = compress(Y)
  for i in range(N):
    Y[i] = mem[Y[i]]
  
  # x, y座標が範囲内の点のみソート
  points = [(i, j) for i, j in zip(X, Y) if X[0] <= i <= X[-1] and Y[0] <= j <= Y[-1]]

  # DP
  ft = FenwickTreeMod(len(mem))
  ft.add(Y[0], 1)
  for i in range(1, len(points) - 1):
    ft.add(points[i][1], ft.sum(points[i][1] + 1))

  # 出力
  print(ft.sum(Y[-1] + 1))
main()