#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
const ll MOD = 998244353;
const ll INF = 1e18;
#define rep(i,m,n) for(ll i = (m); i <= (n); i++)
#define zep(i,m,n) for(ll i = (m); i < (n); i++)
#define rrep(i,m,n) for(ll i = (m); i >= (n); i--)
#define print(x) cout << (x) << endl;
#define printa(x,m,n) for(ll i = (m); i <= n; i++){cout << (x[i]) << " ";} cout<<endl;

const ll MAX = 200008; 
ll n, x[MAX], d[MAX], dp[2*MAX];
P xd[MAX];

template<typename T> class segtree {
private:
    int n,sz,h; vector<T> node, lazy;
    vector<bool> lazyFlag;
    void eval(int k) {
        if(lazyFlag[k]){
            node[k] = lazy[k];
            if(k < n) {
                lazy[k*2] = lazy[k*2+1] = lazy[k];
                lazyFlag[k*2] = lazyFlag[k*2+1] = true;
            }
            lazyFlag[k] = false;
        }
    }

public:
    segtree(const vector<T>& v) : n(1), sz((int)v.size()), h(0){
        while(n < sz) n *= 2, h++;
        node.resize(2*n, numeric_limits<T>::max());
        lazy.resize(2*n); lazyFlag.resize(2*n, false);
        for(int i = 0; i < sz; i++) node[i+n] = v[i];
        for(int i = n - 1; i >= 1; i--) node[i] = min(node[i*2], node[i*2+1]);
    }
    void range(int a, int b, T x, int k=1, int l=0, int r=-1){
        if(r < 0) r = n;
        eval(k);
        if(b <= l || r <= a) return;
        if(a <= l && r <= b){
            lazy[k] = x, lazyFlag[k] = true; eval(k);
        }else{
            range(a, b, x, 2*k, l, (l+r)/2);
            range(a, b, x, 2*k+1, (l+r)/2, r);
            node[k] = min(node[2*k], node[2*k+1]);
        }
    }
    T query(int a, int b) {
        a += n, b += n - 1;
        for(int i = h; i > 0; i--) eval(a >> i), eval(b >> i);
        b++;
        T res1 = numeric_limits<T>::max(), res2 = numeric_limits<T>::max();
        while(a < b) {
            if(a & 1) eval(a), res1 = min(res1, node[a++]);
            if(b & 1) eval(--b), res2 = min(res2, node[b]);
            a >>= 1, b >>= 1;
        }
        return min(res1, res2);
    }
    void _print(){for(int i = 0; i < sz; i++) cout<<query(i,i+1)<< " ";cout<<endl;}
};

int main(){
	cin.tie(0); ios::sync_with_stdio(false);
	
	cin >> n;
	vector<ll> v;
	rep(i, 1, n){
		cin >> x[i] >> d[i];
		v.push_back(x[i]);
		v.push_back(x[i]+d[i]);
	}
	sort(v.begin(), v.end());
	
	map<ll, ll> mp;
	zep(i, 0, v.size()){mp[v[i]] = i+1;}

	rep(i, 1, n){xd[i] = P(mp[x[i]], mp[x[i]+d[i]]);}
	sort(xd+1, xd+n+1);
	
	vector<ll> buf(2*n+1, 0);
	segtree<ll> sg(buf);
	rrep(i, n, 1){
		ll xx = xd[i].first;
		ll dd = xd[i].second;
		ll tmp = -sg.query(xx, dd);
		xd[i].second = max(tmp, dd);
		sg.range(xx, dd, -xd[i].second);
	}
	
	memset(dp, 0, sizeof(dp));
	dp[0] = 1;
	ll at = 0;
	rep(i, 1, n){
		ll xx = xd[i].first;
		ll dd = xd[i].second;
		
		//fetch;
		while(at < xx){
			dp[at+1] += dp[at];
			dp[at+1] %= MOD;
			at++;
		}
		//cout << xx << "," << dd << endl;
		//cout << at << " at" << endl;
		//printa(dp, 0, 2*n)
		//dp[xx+1] += dp[xx];
		//dp[xx+1] %= MOD;
		dp[dd] += dp[xx];
		dp[dd] %= MOD;
		
		//printa(dp, 0, 2*n)
	}
	
	while(at < 2*n){
		dp[at+1] += dp[at];
		dp[at+1] %= MOD;
		at++;
	}
	print(dp[2*n])
	return 0;
}

Measured memory_bytes: 58348