#include <bits/stdc++.h>
using namespace std;

#define lli long long int
#define REP(i,s,n) for(int i=s;i<n;i++)
#define NUM 2520
#define INF (1LL<<50)
#define DEBUG 0
#define mp(a,b) make_pair(a,b)
#define SORT(V) sort(V.begin(),V.end())
#define PI (3.141592653589794)
#define TO_STRING(VariableName) # VariableName
#define LOG(x) if(DEBUG)cout<<TO_STRING(x)<<"="<<x<<" "<<endl;
#define LOG2(x,y) if(DEBUG)cout<<TO_STRING(x)<<"="<<x<<" "<<TO_STRING(y)<<"="<<y<<endl;
#define LOG3(x,y,z) if(DEBUG)cout<<TO_STRING(x)<<"="<<x<<" "<<TO_STRING(y)<<"="<<y<<" "<<TO_STRING(z)<<"="<<z<<endl;
#define LOG4(w,x,y,z) if(DEBUG)cout<<TO_STRING(w)<<"="<<w<<" "<<TO_STRING(x)<<"="<<x<<" "<<TO_STRING(y)<<"="<<y<<" "<<TO_STRING(z)<<"="<<z<<endl;

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; }


const long long MOD = 998244353;

// modint: mod 計算を int を扱うように扱える構造体
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 = 1000000007;
using mint = Fp<MOD>;

mint dp[200100];
bool vis[200100];

vector<lli> X,D;
vector<pair<lli,lli>> v;
map<lli,lli> posToI;
lli N;

mint calc(lli nowI,lli &nexi){
    LOG2(nowI,nexi);
    if(vis[nowI])return dp[nowI];
    vis[nowI]=true;
    mint ans = 1;

    nexi = nowI;
    lli lastI = nowI;
    REP(i,nowI+1,N){
        if(X[nowI]+D[nowI]>X[i]){
            if(!vis[i])ans *= calc(i,nexi);
            i = nexi;
            lastI = i;
        }
        else{break;}
    }
    nexi = lastI;
    LOG3(nowI,nowI,nexi);
    return dp[nowI] = ans+1;
}

void func(){

    REP(i,0,N){
        v.push_back({X[i],D[i]});
    }
    SORT(v);
    REP(i,0,N){
        X[i] = v[i].first;
        D[i] = v[i].second;
    }

    mint ans = 1;
    lli nexi = 0;
    REP(i,0,N){
        if(vis[i])continue;
        ans *= calc(i,nexi);
        i = nexi;
    }
    cout<<ans<<endl;

}

int main(){
    // cout << fixed << setprecision(5);

    scanf("%lld",&N);
    X.resize(N);
    D.resize(N);
    for(int i = 0 ; i < N ; i++){
        scanf("%lld",&X[i]);
        scanf("%lld",&D[i]);
        posToI[X[i]] = i;
    }
    func();
    return 0;
}


Measured memory_bytes: 36388