#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
const int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  }
} iosetup;

template <typename Monoid>
struct RMQ {
  RMQ(int sz, const Monoid UNITY) : UNITY(UNITY) {
    init(sz);
    dat.assign((n << 1) - 1, UNITY);
  }

  RMQ(const vector<Monoid> &a, const Monoid UNITY) : UNITY(UNITY) {
    int a_sz = a.size();
    init(a_sz);
    dat.resize((n << 1) - 1);
    REP(i, a_sz) dat[n - 1 + i] = a[i];
    for (int i = n - 2; i >= 0; --i) dat[i] = max(dat[(i << 1) + 1], dat[(i << 1) + 2]);
  }

  void update(int node, Monoid val) {
    node += n - 1;
    dat[node] = val;
    while (node > 0) {
      node = (node - 1) >> 1;
      dat[node] = max(dat[(node << 1) + 1], dat[(node << 1) + 2]);
    }
  }

  Monoid query(int a, int b) { return query(a, b, 0, 0, n); }

  int find(int a, int b, Monoid val) { return find(a, b, val, 0, 0, n); }

  Monoid operator[](const int idx) const { return dat[idx + n - 1]; }

private:
  int n = 1;
  const Monoid UNITY;
  vector<Monoid> dat;

  void init(int sz) { while (n < sz) n <<= 1; }

  Monoid query(int a, int b, int node, int left, int right) {
    if (right <= a || b <= left) return UNITY;
    if (a <= left && right <= b) return dat[node];
    return max(query(a, b, (node << 1) + 1, left, (left + right) >> 1), query(a, b, (node << 1) + 2, (left + right) >> 1, right));
  }

  int find(int a, int b, Monoid val, int node, int left, int right) {
    if (dat[node] < val || right <= a || b <= left) return -1;
    if (right - left == 1) return node - (n - 1);
    int res_l = find(a, b, val, (node << 1) + 1, left, (left + right) >> 1);
    if (res_l != -1) return res_l;
    return find(a, b, val, (node << 1) + 2, (left + right) >> 1, right);
  }
};

template <typename Abelian>
struct BIT0based {
  BIT0based(int n, const Abelian UNITY = 0) : n(n), UNITY(UNITY), dat(n, UNITY) {}

  void add(int idx, Abelian val) {
    while (idx < n) {
      dat[idx] += val;
      idx |= idx + 1;
    }
  }

  Abelian sum(int idx) {
    Abelian res = UNITY;
    --idx;
    while (idx >= 0) {
      res += dat[idx];
      idx = (idx & (idx + 1)) - 1;
    }
    return res;
  }

  Abelian sum(int left, int right) {
    if (right <= left) return UNITY;
    return sum(right) - sum(left);
  }

  Abelian operator[](const int idx) { return sum(idx, idx + 1); }

  int lower_bound(Abelian val) {
    if (val <= UNITY) return 0;
    int res = 0, exponent = 1;
    while (exponent <= n) exponent <<= 1;
    for (int mask = exponent >> 1; mask > 0; mask >>= 1) {
      if (res + mask - 1 < n && dat[res + mask - 1] < val) {
        val -= dat[res + mask - 1];
        res += mask;
      }
    }
    return res;
  }

private:
  int n;
  const Abelian UNITY;
  vector<Abelian> dat;
};

int mod = MOD;
struct ModInt {
  unsigned val;
  ModInt(): val(0) {}
  ModInt(ll x) : val(x >= 0 ? x % mod : x % mod + mod) {}
  ModInt pow(ll exponent) {
    ModInt tmp = *this, res = 1;
    while (exponent > 0) {
      if (exponent & 1) res *= tmp;
      tmp *= tmp;
      exponent >>= 1;
    }
    return res;
  }
  ModInt &operator+=(const ModInt &x) { if((val += x.val) >= mod) val -= mod; return *this; }
  ModInt &operator-=(const ModInt &x) { if((val += mod - x.val) >= mod) val -= mod; return *this; }
  ModInt &operator*=(const ModInt &x) { val = static_cast<unsigned long long>(val) * x.val % mod; return *this; }
  ModInt &operator/=(const ModInt &x) {
    // assert(__gcd(static_cast<int>(x.val), mod) == 1);
    unsigned a = x.val, b = mod; int u = 1, v = 0;
    while (b) {
      unsigned tmp = a / b;
      swap(a -= tmp * b, b);
      swap(u -= tmp * v, v);
    }
    return *this *= u;
  }
  bool operator==(const ModInt &x) const { return val == x.val; }
  bool operator!=(const ModInt &x) const { return val != x.val; }
  bool operator<(const ModInt &x) const { return val < x.val; }
  bool operator<=(const ModInt &x) const { return val <= x.val; }
  bool operator>(const ModInt &x) const { return val > x.val; }
  bool operator>=(const ModInt &x) const { return val >= x.val; }
  ModInt &operator++() { if (++val == mod) val = 0; return *this; }
  ModInt operator++(int) { ModInt res = *this; ++*this; return res; }
  ModInt &operator--() { val = (val == 0 ? mod : val) - 1; return *this; }
  ModInt operator--(int) { ModInt res = *this; --*this; return res; }
  ModInt operator+() const { return *this; }
  ModInt operator-() const { return ModInt(val ? mod - val : 0); }
  ModInt operator+(const ModInt &x) const { return ModInt(*this) += x; }
  ModInt operator-(const ModInt &x) const { return ModInt(*this) -= x; }
  ModInt operator*(const ModInt &x) const { return ModInt(*this) *= x; }
  ModInt operator/(const ModInt &x) const { return ModInt(*this) /= x; }
  friend ostream &operator<<(ostream &os, const ModInt &x) { return os << x.val; }
  friend istream &operator>>(istream &is, ModInt &x) { ll val; is >> val; x = ModInt(val); return is; }
};
ModInt abs(const ModInt &x) { return x; }
struct Combinatorics {
  int val; // "val!" and "mod" must be disjoint.
  vector<ModInt> fact, fact_inv, inv;
  Combinatorics(int val = 10000000) : val(val), fact(val + 1), fact_inv(val + 1), inv(val + 1) {
    fact[0] = 1;
    FOR(i, 1, val + 1) fact[i] = fact[i - 1] * i;
    fact_inv[val] = ModInt(1) / fact[val];
    for (int i = val; i > 0; --i) fact_inv[i - 1] = fact_inv[i] * i;
    FOR(i, 1, val + 1) inv[i] = fact[i - 1] * fact_inv[i];
  }
  ModInt nCk(int n, int k) {
    if (n < 0 || n < k || k < 0) return ModInt(0);
    // assert(n <= val && k <= val);
    return fact[n] * fact_inv[k] * fact_inv[n - k];
  }
  ModInt nPk(int n, int k) {
    if (n < 0 || n < k || k < 0) return ModInt(0);
    // assert(n <= val);
    return fact[n] * fact_inv[n - k];
  }
  ModInt nHk(int n, int k) {
    if (n < 0 || k < 0) return ModInt(0);
    return (k == 0 ? ModInt(1) : nCk(n + k - 1, k));
  }
};

int main() {
  int n; cin >> n;
  vector<pair<int, int> > xd(n); REP(i, n) cin >> xd[i].first >> xd[i].second;
  sort(ALL(xd));
  RMQ<int> rmq(n, -INF);
  REP(i, n) rmq.update(i, i);
  for (int i = n - 1; i >= 0; --i) {
    int x, d; tie(x, d) = xd[i];
    int r = lower_bound(ALL(xd), make_pair(x + d, 0)) - xd.begin();
    rmq.update(i, rmq.query(i, r));
  }
  // REP(i, n) cout << dp[i] << " \n"[i + 1 == n];
  vector<ModInt> dp(n + 1);
  dp[n] = 1;
  for (int i = n - 1; i >= 0; --i) dp[i] = dp[i + 1] + dp[rmq[i] + 1];
  cout << dp[0] << '\n';
  return 0;
}


Measured memory_bytes: 4608