#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;


template<typename T> class Modular {
private:
  long long value;
  constexpr static int MOD() { return static_cast<int>(T::value); }
public:
  constexpr Modular() : value() {};
  constexpr Modular(const Modular& other) : value(other.value) {}
  template <typename U> constexpr Modular(const U& x) { value = normalize(x); }

  template <typename U> static long long normalize(const U& x) {
    long long v;
    if (-MOD() <= x && x < MOD()) v = static_cast<long long>(x);
    else v = static_cast<long long>(x % MOD());
    if (v < 0) v += MOD();
    return v;
  }

  constexpr static long long inverse(long long x) {
    x = (x % MOD() + MOD()) % MOD();
    long long y = MOD(), u = 1, v = 0;
    while(y) {
      long long t = x / y;
      x -= t * y; swap(x, y);
      u -= t * v; swap(u, v);
    }
    return (u % MOD() + MOD()) % MOD();
  }
  
  static long long mul(const long long& a, const long long& b) {
    long long res;
    #ifdef _WIN32
    unsigned long long x = a * b;
    unsigned xh = (unsigned) (x >> 32), xl = (unsigned) x, d, m;
    asm(
      "divl %4; \n\t"
      : "=a" (d), "=d" (m)
      : "d" (xh), "a" (xl), "r" (MOD())
    );
    res = m;
    #else
    res = a * b % MOD();
    #endif
    return res;
  }

  explicit operator long long() const noexcept { return value;}
  template <typename U> explicit operator U() const noexcept { return static_cast<U>(value); }

  constexpr Modular& operator=(const Modular& other) & noexcept { value = other.value; return *this; }
  template <typename U> constexpr Modular& operator=(const U& other) & noexcept { return *this = Modular(other); }

  constexpr Modular& operator+=(const Modular& other) noexcept { if ((value += other.value) >= MOD()) value -= MOD(); return *this; }
  template <typename U> constexpr Modular& operator+=(const U& other) noexcept { return *this += Modular(other); }

  constexpr Modular& operator-=(const Modular& other) noexcept { if ((value -= other.value) < 0) value += MOD(); return *this; }
  template <typename U> constexpr Modular& operator-=(const U& other) noexcept { return *this -= Modular(other); }

  constexpr Modular& operator*=(const Modular& other) noexcept { this->value = mul(this->value, other.value); return *this; }
  template <typename U> constexpr Modular& operator*=(const U& other) noexcept {return *this *= Modular(other); }

  constexpr Modular& operator/=(const Modular& other) noexcept { return *this *= Modular(inverse(other.value)); }
  template <typename U> constexpr Modular& operator/=(const U& other) noexcept { return *this *= Modular(inverse(normalize(other))); }

  constexpr Modular& operator++() noexcept {return *this += 1; }
  constexpr Modular operator++(int) noexcept { Modular ret(*this); *this += 1; return ret; }

  constexpr Modular& operator--() noexcept {return *this -= 1; }
  constexpr Modular operator--(int) noexcept { Modular ret(*this); *this += 1; return ret; }

  constexpr Modular operator-() const { return Modular(-value); }

  friend constexpr bool operator==(const Modular& lhs, const Modular<T>& rhs) noexcept { return lhs.value == rhs.value; }
  template <typename U> friend constexpr bool operator==(const Modular<T>& lhs, U rhs) noexcept { return lhs == Modular<T>(rhs); }
  template <typename U> friend constexpr bool operator==(U lhs, const Modular<T>& rhs) noexcept { return Modular<T>(lhs) == rhs; }

  friend constexpr bool operator!=(const Modular<T>& lhs, const Modular<T>& rhs) noexcept { return !(lhs == rhs); }
  template <typename U> friend constexpr bool operator!=(const Modular<T>& lhs, U rhs) noexcept { return !(lhs == rhs); }
  template <typename U> friend constexpr bool operator!=(U lhs, const Modular<T> rhs) noexcept { return !(lhs == rhs); }

  friend constexpr bool operator<(const Modular<T>& lhs, const Modular<T>& rhs) noexcept { return lhs.value < rhs.value; }
  template <typename U> friend constexpr bool operator<(const Modular<T> &lhs, U rhs) noexcept { return lhs.value < rhs; }
  template <typename U> friend constexpr bool operator<(U lhs, const Modular<T> &rhs) noexcept { return lhs < rhs.value; }

  friend constexpr bool operator>(const Modular<T>& lhs, const Modular<T>& rhs) noexcept { return rhs.value < lhs.value; }
  template <typename U> friend constexpr bool operator>(const Modular<T> &lhs, U rhs) noexcept { return rhs.value < lhs; }
  template <typename U> friend constexpr bool operator>(U lhs, const Modular<T> &rhs) noexcept { return rhs < lhs.value; }

  friend constexpr bool operator<=(const Modular<T>& lhs, const Modular<T>& rhs) noexcept { return !(lhs.value > rhs.value); }
  template <typename U> friend constexpr bool operator<=(const Modular<T> &lhs, U rhs) noexcept { return !(lhs.value > rhs); }
  template <typename U> friend constexpr bool operator<=(U lhs, const Modular<T> &rhs) noexcept { return !(lhs < rhs.value); }

  friend constexpr bool operator>=(const Modular<T>& lhs, const Modular<T>& rhs) noexcept { return !(lhs.value < rhs.value); }
  template <typename U> friend constexpr bool operator>=(const Modular<T> &lhs, U rhs) noexcept { return !(lhs.value < rhs); }
  template <typename U> friend constexpr bool operator>=(U lhs, const Modular<T> &rhs) noexcept { return !(lhs < rhs.value); }

  friend constexpr Modular<T> operator+(const Modular<T>& lhs, const Modular<T>& rhs) noexcept { return Modular<T>(lhs) += rhs; }
  template <typename U> friend constexpr Modular<T> operator+(const Modular<T>& lhs, U rhs) noexcept { return Modular<T>(lhs) += rhs; }
  template <typename U> friend constexpr Modular<T> operator+(U lhs, const Modular<T> &rhs) noexcept { return Modular<T>(lhs) += rhs; }

  friend constexpr Modular<T> operator-(const Modular<T>& lhs, const Modular<T>& rhs) noexcept { return Modular<T>(lhs) -= rhs; }
  template <typename U> friend constexpr Modular<T> operator-(const Modular<T>& lhs, U rhs) noexcept { return Modular<T>(lhs) -= rhs; }
  template <typename U> friend constexpr Modular<T> operator-(U lhs, const Modular<T> &rhs) noexcept { return Modular<T>(lhs) -= rhs; }

  friend constexpr Modular<T> operator*(const Modular<T>& lhs, const Modular<T>& rhs) noexcept { return Modular<T>(lhs) *= rhs; }
  template <typename U> friend constexpr Modular<T> operator*(const Modular<T>& lhs, U rhs) noexcept { return Modular<T>(lhs) *= rhs; }
  template <typename U> friend constexpr Modular<T> operator*(U lhs, const Modular<T> &rhs) noexcept { return Modular<T>(lhs) *= rhs; }

  friend constexpr Modular<T> operator/(const Modular<T>& lhs, const Modular<T>& rhs) noexcept { return Modular<T>(lhs) /= rhs; }
  template <typename U> friend constexpr Modular<T> operator/(const Modular<T>& lhs, U rhs) noexcept { return Modular<T>(lhs) /= rhs; }
  template <typename U> friend constexpr Modular<T> operator/(U lhs, const Modular<T> &rhs) noexcept { return Modular<T>(lhs) /= rhs; }

  friend std::ostream& operator<<(std::ostream& stream, const Modular<T>& number) noexcept { return stream << number.value; }
  friend std::istream& operator>>(std::istream& stream, Modular<T>& number) { long long in; stream >> in; number.value = Modular<T>::normalize(in); return stream; }
  
  constexpr int getmod() const { return MOD(); }
};

template<typename T, typename U> Modular<T> power(const Modular<T>& x, const U& y) {
  assert(y >= 0);
  Modular<T> k = x, result = 1;
  U p = y;
  while (p > 0) {
    if (p & 1) result *= k;
    k *= k;
    p >>= 1;
  }
  return result;
}

template<typename T> class BinaryCoefficients {
private:
  vector<Modular<T>> fact_, inv_, finv_;
  long long MOD = static_cast<long long>(T::value);
public:
  constexpr BinaryCoefficients(int n = 2020200) : fact_(n, 1), inv_(n, 1), finv_(n, 1) {
    for (int i = 2; i < n; i++) {
      fact_[i] = fact_[i - 1] * i;
      inv_[i] = -inv_[MOD % i] * (MOD / i);
      finv_[i] = finv_[i - 1] * inv_[i];
    }
  }
  constexpr Modular<T> comb(int n, int k) const noexcept { if (n < k || n < 0 || k < 0) return 0; return fact_[n] * finv_[k] * finv_[n - k]; }
  constexpr Modular<T> fact(int n) const noexcept { if (n < 0) return 0; return fact_[n]; }
  constexpr Modular<T> inv(int n) const noexcept { if (n < 0) return 0; return inv_[n]; }
  constexpr Modular<T> finv(int n) const noexcept { if (n < 0) return 0; return finv_[n]; }
};

//constexpr int mod = 1e9 + 7;
constexpr int mod = 998244353;
using mint = Modular<std::integral_constant<decay<decltype(mod)>::type, mod>>;
using bicoef = BinaryCoefficients<std::integral_constant<decay<decltype(mod)>::type, mod>>;

// struct modValue { static int value; };
// int modValue::value;
// int& mod = modValue::value;
// using mint = Modular<modValue>;
// using bicoef = BinaryCoefficients<modValue>;

template<typename Monoid> class SegmentTree {
private:
  using Func = function<Monoid(Monoid, Monoid)>;
  Func func;
  Monoid unity;
  int siz;
  vector<Monoid> data;
  int n;
  int height;
  inline void build() {
    siz = 1;
    while (siz < n) siz <<= 1, ++height;
    data.assign(siz << 1, unity);
    for (int i = 0; i < n; i++) set(i, unity);
    for (int idx = siz - 1; idx > 0; idx--) data[idx] = func(data[(idx << 1) | 0], data[(idx << 1) | 1]);
  }
  template<typename T> inline void build(const T& arr) {
    if (!~n) n = (int) arr.size();
    siz = 1;
    while (siz < n) siz <<= 1, ++height;
    data.assign(siz << 1, unity);
    for (int i = 0; i < n; i++) set(i, arr[i]);
    for (int idx = siz - 1; idx > 0; idx--) data[idx] = func(data[(idx << 1) | 0], data[(idx << 1) | 1]);
  }
  inline void set(int idx, const Monoid& val) { assert(idx + siz < (int) data.size()); data[idx + siz] = val;}

public:
  SegmentTree() {}
  SegmentTree (const Func f, const Monoid& u, const int& n_) : func(f), unity(u), n(n_) { build(); }
  template<typename T> SegmentTree (const T& arr, const Func f, const Monoid& u, int n_ = -1) : func(f), unity(u), n(n_) { build(arr); }
  

  void initialize (const Func f, const Monoid &u, const int& n_) { func = f; unity = u; n = n_; build(); }
  template<typename T> void initialize (const T& arr, const Func f, const Monoid& u, int n_ = -1) { func = f; unity = u; n = n_; buld(arr); }

  void modify (int idx, const Monoid& val) {
    idx += siz;
    data[idx] = val;
    while (idx >>= 1) data[idx] = func(data[(idx << 1) | 0], data[(idx << 1) | 1]);
  }
  //[left, right) 
  Monoid get (int left, int right) {
    if (left > right) swap(left, right);
    Monoid val_left = unity, val_right = unity;
    for (int l = left + siz, r = right + siz; l < r; l >>= 1, r >>= 1) {
      if (l & 1) val_left = func(val_left, data[l++]);
      if (r & 1) val_right = func(data[--r], val_right);
    }
    return func(val_left, val_right);
  }

  template<typename U>
  int find (int start, int left, int right, int cur, Monoid& val, const U& f) {
    if (left + 1 == right) {
      val = func(val, data[cur]);
      return f(val) ? cur - siz : -1;
    }
    int mid = (left + right) >> 1;
    if (mid <= start) return find(start, mid, right, (cur << 1) | 1, val, f);
    if (start <= left && !f(func(val, data[cur]))) {
      val = func(val, data[cur]);
      return -1;
    }
    int val_left = find(start, left, mid, (cur << 1) | 0, val, f);
    if (~val_left) return val_left;
    return find(start, mid, right, (cur << 1) | 1, val, f);
  }
  template<typename U>
  int find (int start, const U& f) {
    Monoid val = unity;
    return find(start, 0, siz, 1, val, f);
  }

  inline Monoid operator[] (int idx) { return data[idx + siz]; }
  void print() {
    for (int i = 0; i < siz; i++) {
      cout << (*this)[i];
      if (i != siz - 1) cout << ", ";
    }
    cout << '\n';
  }
};

// long long max
function<long long(long long, long long)> LLMAX = [] (long long a, long long b) -> long long { return max(a, b); };
const long long LLMAX_UNITY = numeric_limits<long long>::min();
// int max
function<int(int, int)> INTMAX = [] (int a, int b) -> int { return max(a, b); };
const int INTMAX_UNITY = numeric_limits<int>::min();
// long long min
function<long long(long long, long long)> LLMIN = [] (long long a, long long b) -> long long { return min(a, b); };
const long long LLMIN_UNITY = numeric_limits<long long>::max();
// int min
function<int(int, int)> INTMIN = [] (int a, int b) -> int { return min(a, b); };
const int INTMIN_UNITY = numeric_limits<int>::max();
// long long sum
function<long long(long long, long long)> LLSUM = [] (long long a, long long b) -> long long { return a + b; };
const long long LLSUM_UNITY = 0LL;
// int sum
function<int(int, int)> INTSUM = [] (int a, int b) -> int { return a + b; };
const int INTSUM_UNITY = 0;

signed main() {
  ios::sync_with_stdio(false); cin.tie(0);
  int n;
  cin >> n;
  vector<pair<int, int>> in(n + 1);
  for (int i = 0; i < n; i++) cin >> in[i].first >> in[i].second;
  in[n].first = 2e9 + 1;
  sort(in.begin(), in.end());
  //for (auto& p : in) cerr << p.first << " " << p.second << endl;
  SegmentTree<int> sgt(INTMAX, INTMAX_UNITY, n + 10);
  for (int i = 0; i < n; i++) sgt.modify(i, i);
  //for (int i = 0; i < n; i++) cerr << sgt.get(i, i + 1) << endl;
  for (int i = n - 1; i >= 0; i--) {
    auto idx = upper_bound(in.begin(), in.end(), make_pair(in[i].first + in[i].second, -11)) - in.begin();
    sgt.modify(i, sgt.get(i, idx));
  }
  //for (int i = 0; i < n; i++) cerr << sgt.get(i, i + 1) << endl;
  vector<mint> dp(n + 1);
  dp[n] = 1;
  for (int i = n - 1; i >= 0; i--) {
    dp[i] = dp[i + 1] + dp[sgt.get(i, i + 1) + 1];
  }
  cout << dp[0] << endl;
  return 0;
}

Measured memory_bytes: 5504