#include <bits/stdc++.h>
#define For(i, a, b) for(int (i)=(int)(a); (i)<(int)(b); ++(i))
#define rFor(i, a, b) for(int (i)=(int)(a)-1; (i)>=(int)(b); --(i))
#define rep(i, n) For((i), 0, (n))
#define rrep(i, n) rFor((i), (n), 0)
#define fi first
#define se second
using namespace std;
typedef long long lint;
typedef unsigned long long ulint;
typedef pair<int, int> pii;
template<class T> bool chmax(T &a, const T &b){if(a<b){a=b; return true;} return false;}
template<class T> bool chmin(T &a, const T &b){if(a>b){a=b; return true;} return false;}
template<class T> T div_floor(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>=0 ? a/b : (a+1)/b-1;
}
template<class T> T div_ceil(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>0 ? (a-1)/b+1 : a/b;
}

constexpr lint mod = 1e9+7;
constexpr lint INF = mod * mod;
constexpr int MAX = 100010;

template<int_fast64_t MOD> struct modint{
    using i64=int_fast64_t;
    i64 a;
    modint(const i64 a_=0): a(a_){
        if(a>MOD) a%=MOD;
        else if(a<0) (a%=MOD)+=MOD;
    }
    modint inv(){
        i64 t=1, n=MOD-2, x=a;
        while(n){
            if(n&1) (t*=x)%=MOD;
            (x*=x)%=MOD;
            n>>=1;
        }
        modint ret(t);
        return ret;
    }
    bool operator==(const modint x) const{return a==x.a;}
    bool operator!=(const modint x) const{return a!=x.a;}
    modint operator+(const modint x) const{
        return modint(*this)+=x;
    }
    modint operator-(const modint x) const{
        return modint(*this)-=x;
    }
    modint operator*(const modint x) const{
        return modint(*this)*=x;
    }
    modint operator/(const modint x) const{
        return modint(*this)/=x;
    }
    modint operator^(const lint x) const{
        return modint(*this)^=x;
    }
    modint &operator+=(const modint &x){
        a+=x.a;
        if(a>=MOD) a-=MOD;
        return *this;
    }
    modint &operator-=(const modint &x){
        a-=x.a;
        if(a<0) a+=MOD;
        return *this;
    }
    modint &operator*=(const modint &x){
        (a*=x.a)%=MOD;
        return *this;
    }
    modint &operator/=(modint x){
        (a*=x.inv().a)%=MOD;
        return *this;
    }
    modint &operator^=(lint n){
        i64 ret=1;
        while(n){
            if(n&1) (ret*=a)%=MOD;
            (a*=a)%=MOD;
            n>>=1;
        }
        a=ret;
        return *this;
    }
    modint operator-() const{
        return modint(0)-*this;
    }
    modint &operator++(){
        return *this+=1;
    }
    modint &operator--(){
        return *this-=1;
    }
    bool operator<(const modint x) const{
        return a<x.a;
    }
};

using mint=modint<998244353>;

vector<mint> fact;
vector<mint> revfact;

void setfact(int n){
    fact.resize(n+1); revfact.resize(n+1);
    fact[0] = 1;
    rep(i, n) fact[i+1] = fact[i] * mint(i+1);

    revfact[n] = fact[n].inv();
    for(int i=n-1; i>=0; i--) revfact[i] = revfact[i+1] * mint(i+1);
}

mint getC(int n, int r){
    if(n<r) return 0;
    return fact[n] * revfact[r] * revfact[n-r];
}

template<typename T> struct SegTree{
    using F=function<T(T, T)>;
    int sz=1, seq_sz;
    T et;
    F f, g;
    vector<T> node;

    SegTree(int sz_, T et_, F f_, F g_): seq_sz(sz_), et(et_), f(f_), g(g_){
        while(sz<sz_) sz<<=1;
        node.resize(sz<<1, et);
    }

    void build(vector<T> &a){
        rep(i, a.size()) node[i+sz] = a[i];
        rFor(i, sz, 1) node[i] = f(node[i<<1], node[(i<<1)+1]);
    }

    void build(T x){
        rep(i, seq_sz) node[i+sz] = x;
        rFor(i, sz, 1) node[i] = f(node[i<<1], node[(i<<1)+1]);
    }

    void update(int i, T x){
        i+=sz;
        node[i]=g(node[i], x);
        i>>=1;
        while(i){
            node[i]=f(node[i<<1], node[(i<<1)+1]);
            i>>=1;
        }
    }

    T query(int l, int r){
        T vl=et, vr=et;
        for(l+=sz, r+=sz; l<r; l>>=1, r>>=1){
            if(l&1) vl=f(vl, node[l++]);
            if(r&1) vr=f(node[--r], vr);
        }
        return f(vl, vr);
    }

    int search_left(int l, const T val, function<bool(T, T)> cmp, function<bool(T, T)> check){
        T sum = et;
        for(l+=sz; ; l>>=1){
            if(check(f(sum, node[l]), val)){
                while(l < sz){
                    if(check(f(sum, node[l<<1]), val)) l<<=1;
                    else{
                        sum = f(sum, node[l<<1]);
                        l = (l<<1) + 1;
                    }
                }
                return l-sz;
            }
            if(__builtin_popcount(l+1) == 1) return seq_sz;
            if(l&1) sum = f(sum, node[l++]);
        }
    }

    int search_right(int r, const T val, function<bool(T, T)> cmp, function<bool(T, T)> check){
        T sum = et;
        for(r+=sz; ; r>>=1){
            if(check(f(sum, node[r]), val)){
                while(r < sz){
                    if(check(f(node[(r<<1)+1], sum), val)) r = (r<<1) + 1;
                    else{
                        sum = f(node[(r<<1)+1], sum);
                        r<<=1;
                    }
                }
                return r-sz;
            }
            if(__builtin_popcount(r) == 1) return -1;
            if(!(r&1)) sum = f(node[r--], sum);
        }
    }

    int lower_bound_left(int l, const T val, function<bool(T, T)> cmp=less<>()){
        auto check = [&cmp](auto a, auto b){return !cmp(a, b);};
        return search_left(l, val, cmp, check);
    }

    int upper_bound_left(int l, const T val, function<bool(T, T)> cmp=less<>()){
        auto check = [&cmp](auto a, auto b){return cmp(b, a);};
        return search_left(l, val, cmp, check);
    }

    int lower_bound_right(int l, const T val, function<bool(T, T)> cmp=greater<>()){
        auto check = [&cmp](auto a, auto b){return !cmp(b, a);};
        return search_right(l, val, cmp, check);
    }

    int upper_bound_right(int l, const T val, function<bool(T, T)> cmp=greater<>()){
        auto check = [&cmp](auto a, auto b){return cmp(a, b);};
        return search_right(l, val, cmp, check);
    }
};

int main(){
    using pll = pair<lint, lint>;
    int n;
    scanf("%d", &n);
    pll p[n];
    rep(i, n) scanf("%lld %lld", &p[i].fi, &p[i].se);
    sort(p, p+n);

    auto f = [](lint a, lint b){return max(a, b);};
    SegTree<lint> st(n, -INF, f, f);
    lint lim[n];
    lim[n-1] = p[n-1].fi + p[n-1].se;
    st.update(n-1, p[n-1].fi+p[n-1].se);
    rrep(i, n-1){
        st.update(i, p[i].fi+p[i].se);
        int j = lower_bound(p, p+n, make_pair(p[i].fi+p[i].se, 0LL)) - p;
        lim[i] = st.query(i, j);
        st.update(i, lim[i]);
    }

    mint dp[n];
    dp[n-1] = 2;
    rrep(i, n-1){
        int j = lower_bound(p, p+n, make_pair(lim[i], 0LL)) - p;
        dp[i] = dp[i+1] + (j < n ? dp[j] : 1);
    }
    printf("%lld\n", dp[0].a);
}

Measured memory_bytes: 10624