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 = [j for i, j in points] mem = compress(y) for i in range(N): points[i][1] = 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): if points[0][0] <= points[i][0] <= points[-1][0]: ft.add(points[i][1], ft.sum(points[i][1] + 1)) print(ft.sum(points[-1][1] + 1)) main()