/*
このコード、と～おれ!
Be accepted!
∧＿∧　
（｡･ω･｡)つ━☆・*。
⊂　　 ノ 　　　・゜+.
　しーＪ　　　°。+ *´¨)
 　　　　　　　　　.· ´¸.·*´¨) ¸.·*¨)
		  　　　　　　　　　　(¸.·´ (¸.·'* ☆
*/

#include <cstdio>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstring>
#include <vector>
#include <numeric>
#include <iostream>
#include <random>
#include <map>
#include <unordered_map>
#include <queue>
#include <regex>
#include <functional>
#include <complex>
#include <list>
#include <cassert>
#include <iomanip>
#include <set>
/*多倍長整数/cpp_intで宣言
#include <boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;
*/

#pragma gcc target ("avx2")
#pragma gcc optimization ("o3")
#pragma gcc optimization ("unroll-loops")
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define rep1(i, n) for(int i = 1; i <= (n); ++i)
#define rep2(i, n) for(int i = 2; i < (n); ++i)
#define repr(i, n) for(int i = n; i >= 0; --i)
#define reprm(i, n) for(int i = n - 1; i >= 0; --i)
#define printynl(a) printf(a ? "yes\n" : "no\n")
#define printyn(a) printf(a ? "Yes\n" : "No\n")
#define printYN(a) printf(a ? "YES\n" : "NO\n")
#define printim(a) printf(a ? "possible\n" : "imposible\n")
#define printdb(a) printf("%.50lf\n", a) //少数出力
#define printdbd(a) printf("%.16lf\n", a) //少数出力(桁少なめ)
#define prints(s) printf("%s\n", s.c_str()) //string出力
#define all(x) (x).begin(), (x).end()
#define allsum(a, b, c) ((a + b) * c / 2.0) //等差数列の和、初項,末項,項数
#define pb push_back
#define priq priority_queue
#define rpriq priq<int, vector<int>, greater<int>>
#define deg_to_rad(deg) (((deg)/360.0)*2.0*PI)
#define rad_to_deg(rad) (((rad)/2.0/PI)*360.0)
#define Please return
#define AC 0
#define addf(T) [](T a, T b){return (a + b);}
#define minf(T) [](T a, T b){return min(a, b);}
#define maxf(T) [](T a, T b){return max(a, b);}
#define nopf(T) [](T a){return a;}
#define manhattan_dist(a, b, c, d) (abs(a - c) + abs(b - d)) /*(a, b) から (c, d) のマンハッタン距離 */


using ll = long long;

constexpr int INF = 1073741823;
constexpr int MINF = -1073741823;
constexpr ll LINF = ll(4661686018427387903);
constexpr ll MOD = 1000000007;
const long double PI = acos(-1.0L);

using namespace std;

void scans(string& str) {
	char c;
	str = "";
	scanf("%c", &c);
	if (c == '\n')scanf("%c", &c);
	while (c != '\n' && c != -1 && c != ' ') {
		str += c;
		scanf("%c", &c);
	}
}

void scanc(char& str) {
	char c;
	scanf("%c", &c);
	if (c == -1)return;
	while (c == '\n') {
		scanf("%c", &c);
	}
	str = c;
}

double acot(double x) {
	return PI / 2 - atan(x);
}

ll gcd(ll a, ll b) {
	if (b == 0) return a;
	return gcd(b, a % b);
}

ll lcm(ll number1, ll number2) {
	return number1 / gcd(number1, number2) * number2;
}

ll LSB(ll n) { return (n & (-n)); }

/*-----------------------------------------ここからコード-----------------------------------------*/


//セグ木/0-indexed/非再帰/(大きさ, 単位元)で初期化
template<typename T>
struct segtree {
	//木を配列であらわしたもの
	vector<T> seg;
	//木の1/2の大きさ
	int siz;
	//単位元
	const T unit;
	//比較関数の型
	using F = function<T(T, T)>;
	//マージする関数
	const F f;

	//n の大きさ, a (単位元) で segtree を初期化する
	segtree(int n, const T a, const F f) : unit(a), f(f) {
		siz = 1;
		while (siz < n)siz <<= 1;
		seg.assign(2 * siz - 1, unit);
		--siz;
	}

	//k (0-indexed) 番目に t を代入
	void set(int k, const T& t) {
		seg[k + siz] = t;
	}

	//f によって木を構築
	void build() {
		for (int i = siz - 1; i >= 0; --i) seg[i] = f(seg[i * 2 + 1], seg[i * 2 + 2]);
	}

	//i 番目の要素を返す
	T operator[](const int i) {
		return seg[i + siz];
	}

	//k 番目の値を a に更新,更新に使う二項演算
	void update(int k, T a) {
		k += siz;
		//必要であればここを変える
		seg[k] = a;
		while (k > 0) {
			k = ((k - 1) >> 1);
			seg[k] = f(seg[k * 2 + 1], seg[k * 2 + 2]);
		}
	}

	//[a, b) について f した結果を返す
	T query(int a, int b) {
		T l = unit, r = unit;
		for (a += siz, b += siz; 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);
	}

	//[start, end) について、[l, r) を調べながら k 番目が check を満たすか二分探索 最後が true なら left, false なら right fの逆演算
	template<typename C>
	int find(const int start, const int end, int l, int r, int k, const C check, T& checknum, const bool b, const function<T(T, T)> revf) {
		//cerr << checknum << '\n';
		//範囲外またはそこがすでに満たさないとき
		//cerr << k << ',' << checknum << '\n';
		if (start <= l && r <= end && !check(seg[k], checknum)) {
			checknum = revf(checknum, seg[k]);
			return -1;
		}
		if ((r <= start || l >= end)) {
			return -1;
		}
		//既に葉
		if (k >= siz) {
			return k - siz;
		}
		int res;
		if (b) {
			//左側を調べる
			res = find< C >(start, end, l, ((l + r) >> 1), (k << 1) + 1, check, checknum, b, revf);
			//左側が適してたらそれが答え
			if (res != -1)return (res);
			return find< C >(start, end, ((l + r) >> 1), r, (k << 1) + 2, check, checknum, b, revf);
		}
		else {
			//右側を調べる
			res = find< C >(start, end, ((l + r) >> 1), r, (k << 1) + 2, check, checknum, b, revf);
			//右側が適してたらそれが答え
			if (res != -1)return (res);
			return find< C >(start, end, l, ((l + r) >> 1), (k << 1) + 1, check, checknum, b, revf);
		}
	}

	template<typename C>
	int find_left(int start, int end, const C check, T& checknum, function<T(T, T)> revf) {
		return find< C >(start, end, 0, siz + 1, 0, check, checknum, true, revf);
	}

	template<typename C>
	int find_right(int start, int end, const C check, T& checknum, function<T(T, T)> revf) {
		return find< C >(start, end, 0, siz + 1, 0, check, checknum, false, revf);
	}

};

template< int mod >
struct ModInt {
	int x;

	ModInt() : x(0) {}

	ModInt(ll y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

	ModInt& operator+=(const ModInt& p) {
		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 ModInt& p) {
		x = (int)(1LL * x * p.x % mod);
		return *this;
	}

	ModInt& operator/=(const ModInt& p) {
		*this *= p.inverse();
		return *this;
	}

	ModInt operator-() const { return ModInt(-x); }

	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; }

	bool operator>(const ModInt& p) const { return x > p.x; }

	bool operator<(const ModInt& p) const { return x < p.x; }

	bool operator<=(const ModInt& p) const { return x <= p.x; }

	bool operator>=(const ModInt& p) const { return x >= p.x; }

	ModInt inverse() 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(int64_t 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) {
		ll t;
		is >> t;
		a = ModInt< mod >(t);
		return (is);
	}

	static int get_mod() { return mod; }
};

using modint = ModInt< MOD >;//MOD=1e9 + 7
using Modint = ModInt< 998244353 >;

int main() {

	int n;
	scanf("%d", &n);
	vector<pair<int, int>> a(n);
	vector<int> z(n);
	rep(i, n) {
		scanf("%d%d", &a[i].first, &a[i].second);
		z[i] = a[i].first;
	}
	sort(all(a));
	sort(all(z));
	z.erase(unique(all(z)), z.end());
	segtree<int> tree(400000, 0, maxf(int));
	vector<int> r(n);
	reprm(i, n) {
		int reach = distance(z.begin(), lower_bound(all(z), a[i].first + a[i].second));
		r[i] = max(tree.query(i, reach), i);
		tree.update(i, r[i]);
	}
	vector<Modint> dp(200010);
	dp[n] = 1;
	reprm(i, n) {
		dp[i] = dp[i + 1] + dp[r[i] + 1];
	}
	cout << dp[0] << '\n';

	Please AC;
}


Measured memory_bytes: 8320