#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> P;
typedef pair<int,int> Pi;
#define rep(i,n) for(ll i=0;i<n;i++)
#define FOR(i,a,b) for(ll i=a;i<b;i++)
#define fi first
#define se second
#define endl "\n"

template<typename T> inline bool chmax(T &a, T b){if(a<b){a=b;return true;}return false;}
template<typename T> inline bool chmin(T &a, T b){if(a>b){a=b;return true;}return false;}
template<typename T> ostream& operator<<(ostream& s,const complex<T>& d) {return s<<"("<<d.real()<<", "<<d.imag()<< ")";}
template<typename T1, typename T2> ostream& operator<<(ostream& s,const pair<T1,T2>& d) {return s<<"("<<d.first<<", "<<d.second<<")";}
template<typename T> ostream& operator<<(ostream& s, const vector<T>& d){int len=d.size();rep(i,len){s<<d[i];if(i<len-1) s<<" ";}return s;}
template<typename T> ostream& operator<<(ostream& s,const vector<vector<T>>& d){int len=d.size();rep(i,len){s<<d[i]<<endl;}return s;}
template<typename T> ostream& operator<<(ostream& s,const set<T>& v){s<<"{ ";for(auto itr=v.begin();itr!=v.end();++itr) {if (itr!=v.begin()) {s<< ", ";}s<<(*itr);}s<<" }";return s;}
template<typename T1, typename T2> ostream& operator<<(ostream& s,const map<T1,T2>& m){s<<"{"<<endl;for(auto itr=m.begin();itr!=m.end();++itr){s<<" "<<(*itr).first<<" : "<<(*itr).second<<endl;}s<<"}"<<endl;return s;}

const ll mod=998244353;
const ll inf=1e17;
const int INF=1e9;
const double PI=acos(-1);
const double EPS=1e-10;

struct mint{
	ll x;
	mint(ll x=0):x((x%mod+mod)%mod){}
	friend ostream &operator<<(ostream& os,const mint& a){
		return os<<a.x;
	}
	friend istream &operator>>(istream& is,mint& a){
		ll t;
		is>>t;
		a=mint(t);
		return (is);
	}
	mint& operator+=(const mint a){
		if((x+=a.x)>=mod) x-=mod;
		return *this;
	}
	mint& operator-=(const mint a){
		if((x+=mod-a.x)>=mod)x-=mod;
		return *this;
	}
	mint& operator*=(const mint a){
		(x*=a.x)%=mod;
		return *this;
	}
	mint operator+(const mint a) const{
		mint res(*this);
		return res+=a;
	}
	mint operator-(const mint a) const{
		mint res(*this);
		return res-=a;
	}
	mint operator*(const mint a) const{
		mint res(*this);
		return res*=a;
	}
	mint pow(ll t) const{
		if (!t) return 1;
		mint a=pow(t>>1);
		a*=a;
		if(t&1) a*=*this;
		return a;
	}
	// for prime mod
	mint inv() const{
		return pow(mod-2);
	}
	mint& operator/=(const mint a){
		return (*this)*=a.inv();
	}
	mint operator/(const mint a) const{
		mint res(*this);
		return res/=a;
	}
};

struct combination{
  vector<mint> fact,ifact;
  combination(int n):fact(n+1),ifact(n+1){
	assert(n<mod);
	fact[0]=1;
	for(int i=1;i<=n;i++) fact[i]=fact[i-1]*i;
	ifact[n]=fact[n].inv();
	for(int i=n;i>=1;i--) ifact[i-1]=ifact[i]*i;
  }
  mint operator()(int n,int k){
	if (k<0 || k>n) return 0;
	return fact[n]*ifact[k]*ifact[n-k];
  }
};

template<typename Monoid,typename F>
struct SegmentTree{
	int sz;
	vector<Monoid> node;
	const F op;//演算
	const Monoid e;//単位元
	SegmentTree(int n,const F op,const Monoid &e):op(op),e(e){
		sz=1;
		while(sz<n) sz*=2;
		node.assign(2*sz,e);
	}
	void build(const vector<Monoid> &v){
		int n=v.size();
		for(int i=0;i<n;i++) node[i+sz-1]=v[i];
		for(int i=sz-2;i>=0;i--) node[i]=op(node[2*i+1],node[2*i+2]);
	}
	void update(int k,const Monoid &x){
		k+=sz-1;
		node[k]=x;
		while(k>0){
			k=(k-1)/2;
			node[k]=op(node[2*k+1],node[2*k+2]);
		}
	}
	Monoid query(int a,int b,int k=0,int l=0,int r=-1){
		if(r<0) r=sz;
		if(r<=a || b<=l) return e;
		if(a<=l && r<=b) return node[k];
		else{
			Monoid vl=query(a,b,2*k+1,l,(l+r)/2);
			Monoid vr=query(a,b,2*k+2,(l+r)/2,r);
			return op(vl,vr);
		}
	}
	Monoid operator[](const int &k)const{
		return node[k+sz-1];
	}
};

//Compress<ll> comp(a);みたいな感じで
template <class T>
struct Compress{
	int N;
	map<T,int> idx;
	vector<T> cmp;
	Compress(vector<T> v){
		for(auto& x:v) cmp.push_back(x);
		sort(cmp.begin(),cmp.end());
		cmp.erase(unique(cmp.begin(),cmp.end()),cmp.end());
		N=cmp.size();
		for(int i=0;i<N;i++) idx[cmp[i]]=i;
	}
	int id(T val){return idx[val];}//前→後
	T val(int id){return cmp[id];}//後→前
};

int main(){
	cin.tie(0);ios::sync_with_stdio(false);
	ll n;
	cin>>n;
	vector<P> g(n);
	rep(i,n){
		cin>>g[i].fi>>g[i].se;
	}
	sort(begin(g),end(g));
	vector<ll> x(n),d(n),a(n);
	rep(i,n){
		x[i]=g[i].fi;
		d[i]=g[i].se;
		a[i]=i;
	}
	auto op=[](ll a,ll b){return max(a,b);};
	SegmentTree<ll,decltype(op)> seg(n,op,0);
	seg.build(a);
	vector<mint> dp(n+1,0);
	dp[n]=1;
	for(int i=n-1;i>=0;i--){
		ll ind=lower_bound(begin(x),end(x),x[i]+d[i])-begin(x);
		ll j=seg.query(i,ind);
		dp[i]=dp[i+1]+dp[j+1];
		seg.update(i,j);
	}
	cout<<dp[0]<<endl;
}

Measured memory_bytes: 13696