#include <bits/stdc++.h>
#include <unistd.h>
#include <sys/time.h>
#include <stdlib.h>
 
using namespace std;
 
typedef long long ll;
typedef pair<ll,ll> P;
typedef pair<P, ll> T;
 
long long int INF = 1e18;
const ll fact_table = 800008;
double Pi = 3.1415926535897932384626;

priority_queue <ll> pql;
priority_queue <P> pqp;
priority_queue <P> bag;
//big priority queue
priority_queue <ll,vector<ll>,greater<ll> > pqls;
priority_queue <P,vector<P>,greater<P> > pqps;
//small priority queue
//top pop
 
ll dx[8]={1,0,-1,0,1,1,-1,-1};
ll dy[8]={0,1,0,-1,1,-1,-1,1};
char dir[] = "DRUL";
//↓,→,↑,←
 
 
#define p(x) cout<<x<<"\n";
#define el cout<<endl;
#define pe(x) cout<<(x)<<" ";
#define ps(x) cout<<fixed<<setprecision(25)<<x<<endl;
#define pu(x) cout<<(x);
#define pb push_back
// #define lb lower_bound
#define ub upper_bound
#define CLEAR(a) a = decltype(a)(); 
#define pc(x) cout << x << ",";
 
 
ll mod = 998244353;
// ll mod = 1000000007;
  
ll mypow(ll number1,ll number2, ll mod){
 
    if(number2 == 0){
        return 1;
    }else{
        ll number3 = mypow(number1,number2 / 2, mod);
        number3 *= number3;
        number3 %= mod;
        if(number2%2==1){
            number3 *= number1;
            number3 %= mod;
        }
        return number3;
    }
}
ll rui(ll number1,ll number2){
 
    if(number2 == 0){
        return 1;
    }else{
        ll number3 = rui(number1,number2 / 2);
        number3 *= number3;
        number3 %= mod;
        if(number2%2==1){
            number3 *= number1;
            number3 %= mod;
        }
        return number3;
    }
}
ll gcd(ll number1,ll number2){
 
    if(number1 > number2){
        swap(number1,number2);
    }
    if(number1 == 0 || number1 == number2){
        return number2;
    }else{
        return gcd(number2 % number1,number1);
    }
}
void YES(bool condition){
 
    if(condition){
        p("YES");
    }else{
        p("NO");
    }
    return;
}
void Yes(bool condition){
 
    if(condition){
        p("Yes");
    }else{
        p("No");
    }
    return;
}
 
/*
ll fact[fact_table + 5],rfact[fact_table + 5];
 
 
void c3_init(){
    fact[0] = rfact[0] = 1;
    for(ll i=1; i<=fact_table; i++){
        fact[i] = (fact[i-1]*i) % mod;
    }
    rfact[fact_table] = rui(fact[fact_table],mod - 2);
    for(ll i=fact_table; i>=1; i--){
       rfact[i-1] = rfact[i] * i;
       rfact[i-1] %= mod;
    }
    return;}
ll c3(ll n,ll r){
    return (((fact[n] * rfact[r]) % mod ) * rfact[n-r]) % mod;}
*/
bool multicase = false;

ll n,m,num,sum,a,b,c,d,e,h,q,p;
ll w, ans;
ll k;
ll x[500005], y[500005];
char s[500005], t[500005];
ll max_table[500005], ans_table[500005];

struct SegmentTree {
    //SegmentTree seg( vector<ll>(l + 5, INF) );
private:
    ll n;
    vector<ll> node;
 
public:
    SegmentTree(vector<ll> v) {
        ll sz = v.size();
        n = 1; while(n < sz) n *= 2;
        node.resize(2*n-1, -INF);
        for(int i=0; i<sz; i++) node[i+n-1] = v[i];
        for(int i=n-2; i>=0; i--) node[i] = max(node[2*i+1], node[2*i+2]);
    }
 
    void update(ll x, ll val) {
    //a[x]をyに更新(小さい方に更新ではないので注意)
        x += (n - 1);
        node[x] = val;
        while(x > 0) {
            x = (x - 1) / 2;
            node[x] = max(node[2*x+1], node[2*x+2]);
        }
    }
 
    ll getmax(int a, int b, int k=0, int l=0, int r=-1) {
    //[a,b)の最小値を得る
        if(r < 0) r = n;
        if(r <= a || b <= l) return -INF;
        if(a <= l && r <= b) return node[k];
 
        ll vl = getmax(a, b, 2*k+1, l, (l+r)/2);
        ll vr = getmax(a, b, 2*k+2, (l+r)/2, r);
        return max(vl, vr);
    }
};


void solve(){
    cin >> n;
    vector<P> v;
    vector<ll> v1;
    for(ll i=0;i<n;i++){
        cin >> x[i] >> y[i];
        v.pb(P(x[i], x[i] + y[i]));
        v1.pb(i);
    }
    for(ll i=n;i<n+3;i++){
        v1.pb(INF);
    }
    SegmentTree seg( v1 );
    sort(v.begin(), v.end());
    v.pb(P(INF, INF));
    ans_table[n] = 1;
    max_table[n] = -1;
    for(ll i=n-1;i>=0;i--){
        ll ok = i, ng = n;
        while(ng - ok > 1){
            ll mid = (ng + ok) / 2;
            if(v[i].second > v[mid].first){
                ok = mid;
            }else{
                ng = mid;
            }
        }
        ll find = seg.getmax(i, ng);
        max_table[i] = find;
        seg.update(i, find);
    }
    for(ll i=n-1;i>=0;i--){
        ans_table[i] = ans_table[i+1] + ans_table[max_table[i] + 1];
        ans_table[i] %= mod;
    }
    p(ans_table[0]);

    return;
}

int main(){
    // init();
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    ll q;
    if(multicase){
        cin >> q;
    }else{
        q = 1;
    }
    while(q--){
        solve();
    }
    return 0;

}


















Measured memory_bytes: 24300