#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); i++)
#define rrep(i,n) for(int i=(n)-1; i>=0; i--)
#define FOR(i,a,b) for(int i=(a); i<(b); i++)
#define RFOR(i,a,b) for(int i=(b-1); i>=(a); i--)
#define ALL(v) v.begin(), v.end()
#define RALL(v) v.rbegin(), v.rend()
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
#define pb push_back
using ll = long long;
using D = double;
using LD = long double;
using P = pair<int, int>;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

template<int mod> struct Fp {
    long long val;
    constexpr Fp(long long v = 0) noexcept : val(v % mod) {
        if (val < 0) val += mod;
    }
    constexpr int getmod() { return mod; }
    constexpr Fp operator - () const noexcept {
        return val ? mod - val : 0;
    }
    constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
    constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
    constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
    constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
    constexpr Fp& operator += (const Fp& r) noexcept {
        val += r.val;
        if (val >= mod) val -= mod;
        return *this;
    }
    constexpr Fp& operator -= (const Fp& r) noexcept {
        val -= r.val;
        if (val < 0) val += mod;
        return *this;
    }
    constexpr Fp& operator *= (const Fp& r) noexcept {
        val = val * r.val % mod;
        return *this;
    }
    constexpr Fp& operator /= (const Fp& r) noexcept {
        long long a = r.val, b = mod, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b; swap(a, b);
            u -= t * v; swap(u, v);
        }
        val = val * u % mod;
        if (val < 0) val += mod;
        return *this;
    }
    constexpr bool operator == (const Fp& r) const noexcept {
        return this->val == r.val;
    }
    constexpr bool operator != (const Fp& r) const noexcept {
        return this->val != r.val;
    }
    friend constexpr ostream& operator << (ostream &os, const Fp<mod>& x) noexcept {
        return os << x.val;
    }
    friend constexpr Fp<mod> modpow(const Fp<mod> &a, long long n) noexcept {
        if (n == 0) return 1;
        auto t = modpow(a, n / 2);
        t = t * t;
        if (n & 1) t = t * a;
        return t;
    }
};

const int mod = 998244353;
using mint = Fp<mod>;

vector<int> g[200005];

mint cnt(int v){
    mint res = 1;
    for(int next : g[v]){
        res *= cnt(next);
    }
    return res+1;
}

int main(){
    int n; cin >> n;
    vector<P> r(n);
    rep(i,n) cin >> r[i].first >> r[i].second;
    sort(ALL(r));

    set<P> s;
    rrep(i,n){
        int x = r[i].first, d = r[i].second;
        while(!s.empty() && s.begin() -> first < (x+d)){
            g[i].pb(s.begin() -> second);
            s.erase(s.begin());
        }
        s.emplace(x, i);
    }

    mint ans = 1;
    for(P val : s){
        int par = val.second;
        ans *= cnt(par);
    }

    cout << ans << endl;
}


Measured memory_bytes: 22144