/* Aa^~ kokoro ga pyonpyon suru n jaa^~
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*/
#include<bits/stdc++.h>
using namespace std;
#ifndef ONLINE_JUDGE
#define dbg(x...) do { cout << "\033[32;1m " << #x << " -> "; err(x); } while (0)
void err() { cout << "\033[39;0m" << endl; }
template<template<typename...> class T, typename t, typename... A>
void err(T<t> a, A... x) { for (auto v: a) cout << v << ' '; err(x...); }
template<typename T, typename... A>
void err(T a, A... x) { cout << a << ' '; err(x...); }
#else
#define dbg(...)
#endif
typedef long long ll;
typedef pair<int,int> pi;
typedef vector<int> vi;
template<class T> using vc=vector<T>;
template<class T> using vvc=vc<vc<T>>;
template<class T> void mkuni(vector<T>&v)
{
    sort(v.begin(),v.end());
    v.erase(unique(v.begin(),v.end()),v.end());
}
ll rand_int(ll l, ll r) //[l, r]
{
    static mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());
    return uniform_int_distribution<ll>(l, r)(gen);
}
template<class T>
void print(T x,int suc=1)
{
    cout<<x;
    if(suc==1) cout<<'\n';
    else cout<<' ';
}
template<class T>
void print(const vector<T>&v,int suc=1)
{
    for(int i=0;i<v.size();i++)
    print(v[i],i==(int)(v.size())-1?suc:2);
}
#define lson o<<1
#define rson o<<1|1
#define Lson L,mid,lson
#define Rson mid+1,R,rson
int n;
const int maxn=2e5+7;
int mx[maxn<<2];
void modify(int p,int v,int L=0,int R=n-1,int o=1)
{
    if(L==R)
    {
        mx[o]=v;
        return;
    }
    int mid=L+R>>1;
    if(p<=mid) modify(p,v,Lson);
    else modify(p,v,Rson);
    mx[o]=max(mx[lson],mx[rson]);
}
int query(int l,int r,int L=0,int R=n-1,int o=1)
{
    if(l<=L&&r>=R) return mx[o];
    int mid=L+R>>1;
    int ret=0;
    if(l<=mid) ret=max(ret,query(l,r,Lson));
    if(r>mid) ret=max(ret,query(l,r,Rson));
    return ret;
}
const int mod=998244353;
int main()
{
    cin>>n;
    vc<pi> a(n);
    vi R(n);
    vi all;
    for(int i=0;i<n;i++)
    {
        cin>>a[i].first>>a[i].second;
        all.push_back(a[i].first);
    }
    mkuni(all);
    auto getid=[&](int x){
        return lower_bound(all.begin(),all.end(),x)-all.begin();
    };
    for(int i=0;i<n;i++) a[i].first=getid(a[i].first);
    sort(a.begin(),a.end());
    for(int i=n-1;i>=0;i--)
    {
        int tar=all[a[i].first]+a[i].second;
        int id=getid(tar);
        id--;
        if(id<=a[i].first) R[i]=a[i].first;
        else R[i]=max(a[i].first,query(a[i].first+1,id));
        modify(i,R[i]);
        //dbg(i,R[i]);
    }
    vi dp(n+1);
    dp[n]=1;
    for(int i=n-1;i>=0;i--)
        dp[i]=(dp[i+1]+dp[R[i]+1])%mod;
    print(dp[0]);
}

Measured memory_bytes: 6388