#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
const int INF = (1<<30)-1;
const long long LINF = (1LL<<62)-1;
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

template< typename Monoid >
struct SegmentTree {
  using F = function< Monoid(Monoid, Monoid) >;
 
  int sz;
  vector< Monoid > seg;
 
  const F f;
  const Monoid M1;
 
  SegmentTree(int n, const F f, const Monoid &M1) : f(f), M1(M1) {
    sz = 1;
    while(sz < n) sz <<= 1;
    seg.assign(2 * sz, M1);
  }
 
  void set(int k, const Monoid &x) {
    seg[k + sz] = x;
  }
 
  void build() {
    for(int k = sz - 1; k > 0; k--) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }
 
  void update(int k, const Monoid &x) {
    k += sz;
    seg[k] = x;
    while(k >>= 1) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }
 
  Monoid query(int a, int b) {
    Monoid L = M1, R = M1;
    for(a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if(a & 1) L = f(L, seg[a++]);
      if(b & 1) R = f(seg[--b], R);
    }
    return f(L, R);
  }
 
  Monoid operator[](const int &k) const {
    return seg[k + sz];
  }
 
  template< typename C >
  int find_subtree(int a, const C &check, Monoid &M, bool type) {
    while(a < sz) {
      Monoid nxt = type ? f(seg[2 * a + type], M) : f(M, seg[2 * a + type]);
      if(check(nxt)) a = 2 * a + type;
      else M = nxt, a = 2 * a + 1 - type;
    }
    return a - sz;
  }
 
 
  template< typename C >
  int find_first(int a, const C &check) {
    Monoid L = M1;
    if(a <= 0) {
      if(check(f(L, seg[1]))) return find_subtree(1, check, L, false);
      return -1;
    }
    int b = sz;
    for(a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if(a & 1) {
        Monoid nxt = f(L, seg[a]);
        if(check(nxt)) return find_subtree(a, check, L, false);
        L = nxt;
        ++a;
      }
    }
    return -1;
  }
 
  template< typename C >
  int find_last(int b, const C &check) {
    Monoid R = M1;
    if(b >= sz) {
      if(check(f(seg[1], R))) return find_subtree(1, check, R, true);
      return -1;
    }
    int a = sz;
    for(b += sz; a < b; a >>= 1, b >>= 1) {
      if(b & 1) {
        Monoid nxt = f(seg[--b], R);
        if(check(nxt)) return find_subtree(b, check, R, true);
        R = nxt;
      }
    }
    return -1;
  }
};

const int MOD = 998244353;

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  vector<pair<ll, ll>> x(n);
  rep(i, n) cin >> x[i].first >> x[i].second;
  sort(x.begin(), x.end());
  vector<int> seq(n);
  seq[n-1] = n-1;
  SegmentTree<int> seg(n, [](int a, int b) { return max(a, b); }, 0);
  seg.update(n-1, seq[n-1]);
  for (int i = n-2; i >= 0; i--) {
    int r = lower_bound(x.begin(), x.end(), make_pair(x[i].first+x[i].second, 0LL))-x.begin();
    seq[i] = i;
    if (r > i+1)
      seq[i] = max(i, seg.query(i, r));
    seg.update(i, seq[i]);
  }
  vector<ll> dp(n+1, 0);
  dp[n] = 1;
  for (int i = n-1; i >= 0; i--) 
    dp[i] = (dp[i+1]+dp[seq[i]+1])%MOD;
  cout << dp[0] << endl;
  return 0;
}

Measured memory_bytes: 7808