#ifdef DEBUG_IS_VALID
#define DEB 1 
#define _LIBCPP_DEBUG 0
#else
#define DEB 0
#define NDEBUG
#endif

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

#define ALL(g) (g).begin(),(g).end()
#define REP(i, x, n) for(long long i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define RREP(i, x, n) for(long long i = x; i >= n; i--)
#define rrep(i, n) RREP(i,n,0)
#define pb push_back
#define fi first
#define se second
#pragma GCC optimize ("-O3")

using namespace std;

#define DUMPOUT cout
#define dump(...) if(DEB) DUMPOUT<<"  "<<#__VA_ARGS__<<" :["<<__LINE__<<":"<<__FUNCTION__<<"]"<<endl<<"    "; if(DEB) dump_func(__VA_ARGS__)
template<typename T1,typename T2>ostream& operator << (ostream& os, pair<T1,T2> p){cout << "(" << p.first << ", " << p.second << ")"; return os;}
template<typename T>ostream& operator << (ostream& os, vector<T>& vec) { os << "{"; for (int i = 0; i<vec.size(); i++) os << vec[i] << (i + 1 == vec.size() ? "" : ", "); os << "}"; return os; }
template<typename T>ostream& operator << (ostream& os, set<T>& st){cout << "{"; for(auto itr = st.begin(); itr != st.end(); itr++) cout << *itr << (next(itr)!=st.end() ? ", " : ""); cout << "}"; return os;}
template<typename T1,typename T2>ostream& operator << (ostream& os, map<T1,T2> mp){cout << "{"; for(auto itr = mp.begin(); itr != mp.end(); itr++) cout << "(" << (itr->first) << ", " << (itr->second) << ")" << (next(itr)!=mp.end() ? "," : ""); cout << "}"; return os; }

void dump_func(){DUMPOUT << endl;}
template <class Head, class... Tail>void dump_func(Head&& head, Tail&&... tail){ DUMPOUT << head; if (sizeof...(Tail) == 0) { DUMPOUT << " "; } else { DUMPOUT << ", "; } dump_func(std::move(tail)...);}
template<class T> inline bool chmax(T& a,T const& b){if(a>=b) return false; a=b; return true;}
template<class T> inline bool chmin(T& a,T const& b){if(a<=b) return false; a=b; return true;}

using Int = long long;
using ll = long long;
using P = pair<Int,Int>;
using vi = vector<Int>;
using vvi = vector<vi>;
using vp = vector<P>;
using vvp = vector<vp>;

const Int INF = (1LL<<50);

const long long MOD = 998244353;

template <typename T>
struct SegmentTree{
  using F = function<T(T,T)>;
  int n;
  F f;
  T ti;
  vector<T> dat;

  SegmentTree(){}
  SegmentTree(F f,T ti):f(f),ti(ti){}

  void init(int n_){
    n=1;
    while(n<n_) n<<=1;
    dat.assign(n<<1,ti);
  }

  void build(const vector<T> &v){
    int n_=v.size();
    init(n_);
    for(int i=0;i<n_;i++) dat[n+i]=v[i];
    for(int i=n-1;i;i--)
      dat[i]=f(dat[(i<<1)|0],dat[(i<<1)|1]);
  }

  void update(int k,T x){
    dat[k+=n]=x;
    while(k>>=1)
      dat[k]=f(dat[(k<<1)|0],dat[(k<<1)|1]);
  }

  T query(int a,int b){
    if(a>=b) return ti;
    T vl=ti,vr=ti;
    for(int l=a+n,r=b+n;l<r;l>>=1,r>>=1) {
      if(l&1) vl=f(vl,dat[l++]);
      if(r&1) vr=f(dat[--r],vr);
    }
    return f(vl,vr);
  }

  template<typename C>
  int find(int st,C &check,T &acc,int k,int l,int r){
    if(l+1==r){
      acc=f(acc,dat[k]);
      return check(acc)?k-n:-1;
    }
    int m=(l+r)>>1;
    if(m<=st) return find(st,check,acc,(k<<1)|1,m,r);
    if(st<=l&&!check(f(acc,dat[k]))){
      acc=f(acc,dat[k]);
      return -1;
    }
    int vl=find(st,check,acc,(k<<1)|0,l,m);
    if(~vl) return vl;
    return find(st,check,acc,(k<<1)|1,m,r);
  }

  template<typename C>
  int find(int st,C &check){
    T acc=ti;
    return find(st,check,acc,1,0,n);
  }
};

template <typename T>
struct Compression{
  vector<T> ary;
  #ifdef DEBUG_IS_VALID
    bool built = false;
  #endif
  Compression() : ary(vector<T>()) {;}
  void push(T val){
    ary.push_back(val);
  }
  void build(){
    #ifdef DEBUG_IS_VALID
      built = true;
    #endif
    sort(ary.begin(), ary.end());
    ary.erase(unique(ary.begin(), ary.end()), ary.end());
  }
  int size(){
    #ifdef DEBUG_IS_VALID
      assert(built);
    #endif
    return ary.size();
  }
  T f(int idx){
    #ifdef DEBUG_IS_VALID
      assert(built);
    #endif
    assert(0 <= idx && idx < ary.size());
    return ary[idx];
  }
  int inv(T val){
    #ifdef DEBUG_IS_VALID
      assert(built);
    #endif
    int idx = int(lower_bound(ary.begin(), ary.end(), val) - ary.begin());
    return idx;
  }
};

template<int MOD> struct ModInt {
  static const int Mod = MOD; unsigned x; ModInt() : x(0) { }
  ModInt(signed sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
  ModInt(signed long long sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
  int get() const { return (int)x; }
  ModInt &operator+=(ModInt that) { if ((x += that.x) >= MOD) x -= MOD; return *this; }
  ModInt &operator-=(ModInt that) { if ((x += MOD - that.x) >= MOD) x -= MOD; return *this; }
  ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; }
  ModInt &operator/=(ModInt that) { return *this *= that.inverse(); }
  ModInt operator+(ModInt that) const { return ModInt(*this) += that; }
  ModInt operator-(ModInt that) const { return ModInt(*this) -= that; }
  ModInt operator*(ModInt that) const { return ModInt(*this) *= that; }
  ModInt operator/(ModInt that) const { return ModInt(*this) /= that; }
  ModInt inverse() const { long long a = x, b = MOD, u = 1, v = 0;
      while (b) { long long t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); }
      return ModInt(u); }
  bool operator==(ModInt that) const { return x == that.x; }
  bool operator!=(ModInt that) const { return x != that.x; }
  ModInt operator-() const { ModInt t; t.x = x == 0 ? 0 : Mod - x; return t; }
};
template<int MOD> ostream& operator<<(ostream& st, const ModInt<MOD> a) { st << a.get(); return st; };
template<int MOD> ModInt<MOD> operator^(ModInt<MOD> a, unsigned long long k) {
  ModInt<MOD> r = 1; while (k) { if (k & 1) r *= a; a *= a; k >>= 1; } return r; }
template<typename T, int FAC_MAX> struct Comb { vector<T> fac, ifac;
  Comb(){fac.resize(FAC_MAX,1);ifac.resize(FAC_MAX,1); for(int i = 1; i < FAC_MAX; i++)fac[i]=fac[i-1]*i;
    ifac[FAC_MAX-1]=T(1)/fac[FAC_MAX-1];for(int i = FAC_MAX-2; i >= 1; i--)ifac[i]=ifac[i+1]*T(i+1);}
    T aPb(int a, int b) { if (b < 0 || a < b) return T(0); return fac[a] * ifac[a - b]; }
    T aCb(int a, int b) { if (b < 0 || a < b) return T(0); return fac[a] * ifac[a - b] * ifac[b]; }
    T nHk(int n, int k) { if (n == 0 && k == 0) return T(1); if (n <= 0 || k < 0) return 0;
    return aCb(n + k - 1, k); }}; // nHk = (n+k-1)Ck : n is separator

using mint =  ModInt<MOD>;
using vm =  vector<mint>;

void solve(long long N, std::vector<long long> X, std::vector<long long> D){
  // auto f = [&](P l, P r){return max(l, r); };
  // SegmentTree<P> seg(f, {-INF, -INF});
  // Compression<Int> comp;
  // rep(i, N){
  //   comp.push(X[i]);
  //   comp.push(X[i] + D[i] - 1);
  // }
  // comp.build();
  // Int sz = comp.size();
  // seg.init(sz + 4);
  vvi g(N);
  vi idx(N);
  iota(ALL(idx), 0LL);
  sort(ALL(idx), [&](Int l, Int r){return X[l] < X[r];});
  // for(auto i : idx){
  //   Int par = seg.query(comp.inv(X[i]), sz+1).se;
  //   if(par != -INF){
  //     g[par].pb(i);
  //   }
  //   seg.update(comp.inv(X[i] + D[i] - 1), {X[i], i});
  // }
  set<P> st;
  rrep(ii, N-1){
    Int i = idx[ii];
    while(st.size() && st.begin()->fi < X[i] + D[i]){
      g[i].pb(st.begin()->se);
      st.erase(st.begin());
    }
    st.insert({X[i], i});
  }
  vector<bool> pass(N, false);
  mint ans = 1;
  vector<vm> dp(N, vm(2));
  function<void(Int)> dfs = [&](Int u){
    pass[u] = true;
    if(g[u].size() == 0){
      dp[u][0] = dp[u][1] = mint(1);
      return;
    }
    dp[u][1] = mint(1);
    mint val = mint(1);
    for(auto v: g[u]){
      dfs(v);
      val *= (dp[v][0] + dp[v][1]);
    }
    dp[u][0] = val;
  };
  for(auto i : idx){
    if(!pass[i]){
      dfs(i);
      ans *= (dp[i][0] + dp[i][1]);
      dump(i, ans);
    }
  }
  cout << ans << endl;
}

int main(){
  std::cout << std::fixed << std::setprecision(15);
  long long N;
  scanf("%lld",&N);
  std::vector<long long> X(N);
  std::vector<long long> D(N);
  for(int i = 0 ; i < N ; i++){
    scanf("%lld",&X[i]);
    scanf("%lld",&D[i]);
  }
  solve(N, std::move(X), std::move(D));
  return 0;
}


Measured memory_bytes: 45568