#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;

#define REP(i,n) for(long long i = 0; i < (n); i++)
#define FOR(i, m, n) for(long long i = (m);i < (n); ++i)
#define ALL(obj) (obj).begin(),(obj).end()
#define SPEED cin.tie(0);ios::sync_with_stdio(false);

template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>;

constexpr long long MOD = (long long)1e9 + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433;

template <class T> vector<T> multivector(size_t N,T init){return vector<T>(N,init);}
template <class... T> auto multivector(size_t N,T... t){return vector<decltype(multivector(t...))>(N,multivector(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> inline void chmax(T& a, const T b){a=max(a,b);}
template <class T> inline void chmin(T& a, const T b){a=min(a,b);}
void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;}


template<class Operator> class SegmentTree {
	Operator Op;                            //Operator 演算子、型、単位元を持つ
	using typeNode = decltype(Op.unitNode); //nodeの型
	size_t length;                          //セグメント木の最下段の要素の数(vectorの要素の数を超える2べきの数)
	vector<typeNode> node;                  //ノード

public:

	//unitで初期化
	SegmentTree(const size_t num){
		for (length = 1; length < num; length *= 2);
		node.resize(2 * length, Op.unitNode);
	}

	//vectorで初期化
	SegmentTree(const vector<typeNode> & vec){
		for (length = 1; length < vec.size(); length *= 2);
		node.resize(2 * length, Op.unitNode);
		for (int i = 0; i < vec.size(); ++i) node[i + length] = vec[i];
		for (int i = length - 1; i >= 0; --i) node[i] = Op.funcNode(node[(i<<1)+0],node[(i<<1)+1]);
	}
 
	//同じinitで初期化
	SegmentTree(const size_t num, const typeNode init) {
		for (length = 1; length < num; length *= 2);
		node.resize(2 * length, init);
	}
	
	//idx : 0-indexed
	void update(size_t idx, const typeNode var) {
		if(idx < 0 || length <= idx) return;
		idx += length;
		node[idx] = Op.funcMerge(node[idx],var);
		while(idx >>= 1) node[idx] = Op.funcNode(node[(idx<<1)+0],node[(idx<<1)+1]);
	}

	//[l,r)
	typeNode get(int l, int r) {
		if (l < 0 || length <= l || r < 0 || length < r) return Op.unitNode;
		typeNode vl = Op.unitNode, vr = Op.unitNode;
		for(l += length, r += length; l < r; l >>=1, r >>=1) {
			if(l&1) vl = Op.funcNode(vl,node[l++]);
			if(r&1) vr = Op.funcNode(node[--r],vr);
		}
		return Op.funcNode(vl,vr);
	}
 
	void print(){
		cout << "{ " << get(0,1);
		for(int i = 1; i < length; ++i) cout << ", " << get(i,i+1);
		cout << " }" << endl;

		for(int i = 1,j = 1; i < 2*length; ++i) {
			cout << node[i] << " ";
			if(i==((1<<j)-1) && ++j) cout << endl;
		}
	}

};

//一点加算 区間最大
template<class typeNode> struct nodeSumRangeMax {
	typeNode unitNode = 0;
	typeNode funcNode(typeNode l,typeNode r){return max(l,r);}
	typeNode funcMerge(typeNode l,typeNode r){return l+r;}
};

//一点加算 区間総和
template<class typeNode> struct nodeSumRangeSum {
	typeNode unitNode = 0;
	typeNode funcNode(typeNode l,typeNode r){return l+r;}
	typeNode funcMerge(typeNode l,typeNode r){return l+r;}
};

//一点更新 区間最小
template<class typeNode> struct nodeUpdateRangeMin {
	typeNode unitNode = (1LL<<31)-1;
	typeNode funcNode(typeNode l,typeNode r){return min(l,r);}
	typeNode funcMerge(typeNode l,typeNode r){return r;}
};

//一点更新 区間最小
template<class typeNode> struct nodeUpdateRangeMax {
	typeNode unitNode = -1;
	typeNode funcNode(typeNode l,typeNode r){return max(l,r);}
	typeNode funcMerge(typeNode l,typeNode r){return r;}
};

template<class Operator> class LazySegmentTree {
    Operator Op;                                         //Operator 演算子、型、単位元を持つ
	using typeNode = decltype(Op.unitNode);              //nodeの型
	using typeLazy = decltype(Op.unitLazy);              //lazyの型
	size_t length;                                       //セグメント木の最下段の要素の数(vectorの要素の数を超える2べきの数)
	size_t height;                                       //セグメント木の高さ 
	vector<typeNode> node;                               //node
	vector<typeLazy> lazy;                               //lazy
	vector<int> width;                                   //width
public:

	//unitで初期化
	LazySegmentTree(const size_t num) {
		for (length = 1,height = 0; length < num; length *= 2, height++);
		node.resize(2 * length, Op.unitNode);
		lazy.resize(2 * length, Op.unitLazy);
		width.resize(2 * length, 0);
		for (int i = 0; i < num; ++i) node[i + length] = Op.unitNode;
		for (int i = length - 1; i >= 0; --i) node[i] = Op.funcNode(node[(i<<1)+0],node[(i<<1)+1]);
		for(int i = length; i < 2*length; ++i) for(int j = i, k = 1; j && !width[j] ; j >>= 1,k <<= 1) width[j] = k;
	}

	// //同じinitで初期化
	LazySegmentTree(const size_t num, const typeNode init) {
		for (length = 1,height = 0; length < num; length *= 2, height++);
		node.resize(2 * length, Op.unitNode);
		lazy.resize(2 * length, Op.unitLazy);
		for (int i = 0; i < num; ++i) node[i + length] = init;
		for (int i = length - 1; i >= 0; --i) node[i] = Op.funcNode(node[(i<<1)+0],node[(i<<1)+1]);
		width.resize(2 * length, 0);
		for(int i = length; i < 2*length; ++i) for(int j = i, k = 1; j && !width[j] ; j >>= 1,k <<= 1) width[j] = k;
	}

	//vectorで初期化
	LazySegmentTree(const vector<typeNode>& vec) {
		for (length = 1,height = 0; length < vec.size(); length *= 2, height++);
		node.resize(2 * length, Op.unitNode);
		lazy.resize(2 * length, Op.unitLazy);
		for (int i = 0; i < vec.size(); ++i) node[i + length] = vec[i];
		for (int i = length - 1; i >= 0; --i) node[i] = Op.funcNode(node[(i<<1)+0],node[(i<<1)+1]);
		width.resize(2 * length, 0);
		for(int i = length; i < 2*length; ++i) for(int j = i, k = 1; j && !width[j] ; j >>= 1,k <<= 1) width[j] = k;
	}


	void propagate(int k) {
		if(lazy[k] == Op.unitLazy) return;
		node[k] = Op.funcMerge(node[k],lazy[k],width[k]);
		if(k < length) lazy[2*k+0] = Op.funcLazy(lazy[2*k+0],lazy[k]);
		if(k < length) lazy[2*k+1] = Op.funcLazy(lazy[2*k+1],lazy[k]);
		lazy[k] = Op.unitLazy;
    }


	//idx : 0-indexed
    void update(int a, int b, typeLazy x) {
		int l = a + length, r = b + length - 1;
		for (int i = height; 0 < i; --i) propagate(l >> i), propagate(r >> i);
		for(r++; l < r; l >>=1, r >>=1) {
			if(l&1) lazy[l] = Op.funcLazy(lazy[l],x), propagate(l),l++;
			if(r&1) --r,lazy[r] = Op.funcLazy(lazy[r],x), propagate(r);
		}
		l = a + length, r = b + length - 1;
		while ((l>>=1),(r>>=1),l) {
			if(lazy[l] == Op.unitLazy) node[l] = Op.funcNode(Op.funcMerge(node[(l<<1)+0],lazy[(l<<1)+0],width[(l<<1)+0]),Op.funcMerge(node[(l<<1)+1],lazy[(l<<1)+1],width[(l<<1)+1]));
			if(lazy[r] == Op.unitLazy) node[r] = Op.funcNode(Op.funcMerge(node[(r<<1)+0],lazy[(r<<1)+0],width[(r<<1)+0]),Op.funcMerge(node[(r<<1)+1],lazy[(r<<1)+1],width[(r<<1)+1]));
		}
    }

	//[l,r)
	typeNode get(int a, int b) {
		int l = a + length, r = b + length - 1;
		for (int i = height; 0 < i; --i) propagate(l >> i), propagate(r >> i);
		typeNode vl = Op.unitNode, vr = Op.unitNode;
		for(r++; l < r; l >>=1, r >>=1) {
			if(l&1) vl = Op.funcNode(vl,Op.funcMerge(node[l],lazy[l],width[l])),l++;
			if(r&1) r--,vr = Op.funcNode(Op.funcMerge(node[r],lazy[r],width[r]),vr);
		}
		return Op.funcNode(vl,vr);
	}

	void print(){
		// cout << "node" << endl;
		// for(int i = 1,j = 1; i < 2*length; ++i) {
		// 	cout << node[i] << " ";
		// 	if(i==((1<<j)-1) && ++j) cout << endl;
		// }
		// cout << "lazy" << endl;
		// for(int i = 1,j = 1; i < 2*length; ++i) {
		// 	cout << lazy[i] << " ";
		// 	if(i==((1<<j)-1) && ++j) cout << endl;
		// }
		// cout << "width" << endl;
		// for(int i = 1,j = 1; i < 2*length; ++i) {
		// 	cout << width[i] << " ";
		// 	if(i==((1<<j)-1) && ++j) cout << endl;
		// }
		cout << "vector" << endl;
		cout << "{ " << get(0,1);
		for(int i = 1; i < length; ++i) cout << ", " << get(i,i+1);
		cout << " }" << endl;
	}

};

//node:総和　lazy:加算
template<class typeNode, class typeLazy> struct nodeSumLazyAdd {
	typeNode unitNode = 0;
	typeLazy unitLazy = 0;
	typeNode funcNode(typeNode l,typeNode r){return l+r;}
	typeLazy funcLazy(typeLazy l,typeLazy r){return l+r;}
	typeNode funcMerge(typeNode l,typeLazy r,int len){return l+r*len;}
    // LazySegmentTree<nodeSumLazyPlus<ll,ll>> Seg(N,0);
};

//node:最小　lazy:加算
template<class typeNode, class typeLazy> struct nodeMinLazyAdd {
	typeNode unitNode = 1234567890;
	typeLazy unitLazy = 0;
	typeNode funcNode(typeNode l,typeNode r){return min(l,r);}
	typeLazy funcLazy(typeLazy l,typeLazy r){return l+r;}
	typeNode funcMerge(typeNode l,typeLazy r,int len){return l+r;}
    // LazySegmentTree<nodeMinLazyAdd<ll,ll>> Seg(N,0);
	//verify https://onlinejudge.u-aizu.ac.jp/problems/DSL_2_H
};

//node:mod和　lazy:mod加算
template<class typeNode, class typeLazy> struct nodeModSumLazyModAdd {
	typeNode unitNode = 0;
	typeLazy unitLazy = 0;
	typeNode funcNode(typeNode l,typeNode r){return (l+r)%MOD;}
	typeLazy funcLazy(typeLazy l,typeLazy r){return (l+r)%MOD;}
	typeNode funcMerge(typeNode l,typeLazy r,int len){return (l+(r*len)%MOD)%MOD;}
	// LazySegmentTree<nodeModSumLazyModAdd<ll,ll>> dp(N+3,0);
    //verify https://atcoder.jp/contests/code-festival-2018-quala/tasks/code_festival_2018_quala_d
};

//node:最大　lazy:更新
template<class typeNode, class typeLazy> struct nodeMaxLazyUpdate {
	typeNode unitNode = 0;
	typeLazy unitLazy = 0;
	typeNode funcNode(typeNode l,typeNode r){return max(l,r);}
	typeLazy funcLazy(typeLazy l,typeLazy r){return r;}
	typeNode funcMerge(typeNode l,typeLazy r,int len){return r!=0?r*len:l;}
    // LazySegmentTree<nodeMaxLazyUpdate<ll,ll>> Seg(N+2,0);
    //verify https://atcoder.jp/contests/nikkei2019-final/tasks/nikkei2019_final_d
};

//node:最小　lazy:更新
template<class typeNode, class typeLazy> struct nodeMinLazyUpdate {
	typeNode unitNode = 12345678910;
	typeLazy unitLazy = 0;
	typeNode funcNode(typeNode l,typeNode r){return min(l,r);}
	typeLazy funcLazy(typeLazy l,typeLazy r){return r;}
	typeNode funcMerge(typeNode l,typeLazy r,int len){return r!=0?r*len:l;}
	//LazySegmentTree<ll,ll,nodeMinLazyUpdate<ll,ll>> Seg(N,HIGHINF,0);
    //verify https://atcoder.jp/contests/code-festival-2018-final/tasks/code_festival_2018_final_e
};

//node:GCD　lazy:更新
template<class typeNode, class typeLazy> struct nodeGCDLazyUpdate {
	typeNode unitNode = 0;
	typeLazy unitLazy = 0;
	typeNode funcNode(typeNode l,typeNode r){return ((r == 0) ? l : funcNode(r, l % r));}
	typeLazy funcLazy(typeLazy l,typeLazy r){return r;}
	typeNode funcMerge(typeNode l,typeLazy r,int len){return r!=0?r:l;}
    // LazySegmentTree<nodeGCDLazyUpdate<ll,ll>> Seg(A);
    //verify https://atcoder.jp/contests/abc125/tasks/abc125_c
};

//node:総和　lazy:更新
template<class typeNode, class typeLazy> struct nodeSumLazyUpdate {
	typeNode unitNode = 0;
	typeLazy unitLazy = -2000;
	typeNode funcNode(typeNode l,typeNode r){return l+r;}
	typeLazy funcLazy(typeLazy l,typeLazy r){return r;}
	typeNode funcMerge(typeNode l,typeLazy r,int len){return r!=-2000?r*len:l;}
	// LazySegmentTree<nodeSumLazyUpdate<ll,ll>> Seg(N,0,-2000,0);
    //verify https://onlinejudge.u-aizu.ac.jp/problems/DSL_2_I
};


template<long long mod> class ModInt {
public:
	long long x;
	ModInt():x(0) {
		// do nothing
	}
	ModInt(long long y) : x(y>=0?(y%mod): (mod - (-y)%mod)%mod) {
		// do nothing
	}
	ModInt &operator+=(const ModInt &p) {
		if((x += p.x) >= mod) x -= mod;
		return *this;
	}
	ModInt &operator+=(const long long y) {
        ModInt p(y);
		if((x += p.x) >= mod) x -= mod;
		return *this;
	}
	ModInt &operator+=(const int y) {
        ModInt p(y);
		if((x += p.x) >= mod) x -= mod;
		return *this;
	}
	ModInt &operator-=(const ModInt &p) {
		if((x += mod - p.x) >= mod) x -= mod;
		return *this;
	}
	ModInt &operator-=(const long long y) {
        ModInt p(y);
		if((x += mod - p.x) >= mod) x -= mod;
		return *this;
	}
	ModInt &operator-=(const int y) {
        ModInt p(y);
		if((x += mod - p.x) >= mod) x -= mod;
		return *this;
	}
	ModInt &operator*=(const ModInt &p) {
		x = (x * p.x % mod);
		return *this;
	}
	ModInt &operator*=(const long long y) {
        ModInt p(y);
		x = (x * p.x % mod);
		return *this;
	}
	ModInt &operator*=(const int y) {
        ModInt p(y);
		x = (x * p.x % mod);
		return *this;
	}
	ModInt &operator/=(const ModInt &p) {
		*this *= p.inv();
		return *this;
	}
	ModInt &operator/=(const long long y) {
        ModInt p(y);
		*this *= p.inv();
		return *this;
	}
	ModInt &operator/=(const int y) {
        ModInt p(y);
		*this *= p.inv();
		return *this;
	}
	ModInt operator=(const int y) {
        ModInt p(y);
        *this = p;
        return *this;
    }
    ModInt operator=(const long long y) {
        ModInt p(y);
		*this = p;
        return *this;
    }
	ModInt operator-() const { return ModInt(-x); }
	ModInt operator++() { 
        x++;
        if(x>=mod) x-=mod;
        return *this; 
    }
	ModInt operator--() { 
        x--;
        if(x<0) x+=mod;
        return *this; 
    }
	ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
	ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
	ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
	ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
	bool operator==(const ModInt &p) const { return x == p.x; }
	bool operator!=(const ModInt &p) const { return x != p.x; }
	ModInt inv() const {
		int a = x, b = mod, u = 1, v = 0, t;
		while(b > 0) {
			t = a / b;
			swap(a -= t * b, b);
			swap(u -= t * v, v);
		}
		return ModInt(u);
	}
	ModInt pow(long long n) const {
		ModInt ret(1), mul(x);
		while(n > 0) {
			if(n & 1) ret *= mul;
			mul *= mul;
			n >>= 1;
		}
		return ret;
	}
	friend ostream &operator<<(ostream &os, const ModInt &p) {
		return os << p.x;
	}
	friend istream &operator>>(istream &is, ModInt &a) {
		long long t;
		is >> t;
		a = ModInt<mod>(t);
		return (is);
	}
};
using modint = ModInt<MOD2>;

int main() {
	int N; cin >> N;
	vector<ll> X(N,LOWINF),D(N,LOWINF),Y(N+1,LOWINF),E(N+1,LOWINF);
	for(int i = 0; i < N; ++i) cin >> X[i] >> D[i];
	vector<pair<ll,ll>> ord(N);
	for(int i = 0; i < N; ++i) ord[i] = {X[i],i};
	sort(ALL(ord));
	for(int i = 0; i < N; ++i) Y[i] = X[ord[i].second];
	for(int i = 0; i < N; ++i) E[i] = D[ord[i].second];
	SegmentTree<nodeUpdateRangeMax<int>> Seg(N);
	Seg.update(N-1,N-1);
	for(int i = N-2; 0 <= i; --i){
		int l = i, r = (lower_bound(ALL(Y),Y[i]+E[i]) - Y.begin());
		int j = max(Seg.get(l,r),i);
		Seg.update(i,j);
	}
	LazySegmentTree<nodeSumLazyAdd<modint,modint>> dp(N+1,1);
	for(int i = 0; i < N; ++i) {
		int l = Seg.get(i,i+1) + 1, r = N+1;
		dp.update(l,r,dp.get(i,i+1));
	}
	cout << dp.get(N,N+1) << endl;
	return 0;
}


Measured memory_bytes: 21888