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

template<int64_t MOD> class ModInt {
public:
    int64_t x;
    constexpr ModInt() : x(0) {}
    constexpr ModInt(int64_t v) : x((v % MOD + MOD) % MOD) {}
    constexpr ModInt operator - () const noexcept { return x ? MOD - x : 0;}
    constexpr ModInt operator + (const ModInt a) const noexcept { return ModInt(*this) += a;}
    constexpr ModInt operator - (const ModInt a) const noexcept { return ModInt(*this) -= a;}
    constexpr ModInt operator * (const ModInt a) const noexcept { return ModInt(*this) *= a;}
    constexpr ModInt operator / (const ModInt a) const noexcept { return ModInt(*this) /= a;}
    constexpr ModInt operator / (const int64_t a) const noexcept { return ModInt(*this) /= a;}
    constexpr ModInt operator += (const ModInt a) noexcept {
        x += a.x;
        if (x >= MOD) x -= MOD;
        return *this;
    }
    constexpr ModInt operator += (const int64_t a) noexcept {
        auto hs = ModInt<MOD>(a);
        (*this) += hs;
        return *this;
    }
    constexpr ModInt operator -= (const ModInt a) noexcept {
        if (x < a.x) x += MOD;
        x -= a.x;
        return *this;
    }
    constexpr ModInt operator -= (const int64_t a) noexcept {
        auto hs = ModInt<MOD>(a);
        (*this) -= hs;
        return *this;
    }
    constexpr ModInt operator *= (const ModInt a) noexcept {
        x = x * a.x % MOD;
        return *this;
    }
    constexpr ModInt operator *= (const int64_t a) noexcept {
        auto hs = ModInt<MOD>(a);
        (*this) *= hs;
        return *this;
    }
    constexpr ModInt &operator /= (ModInt a) noexcept {
        int64_t exp = MOD - 2;
        while (exp > 0) {
            if (exp & 1ul) *this *= a;
            a *= a;
            exp >>= 1ul;
        }
        return *this;
    }
    constexpr ModInt &operator /= (int64_t a) noexcept {
        auto hs = ModInt<MOD>(a);
        (*this) /= hs;
        return *this;
    }
    constexpr ModInt &operator ++ () noexcept {
        if (++x >= MOD) x -= MOD;
        return *this;
    }
    constexpr ModInt &operator -- () noexcept {
        if (x-- == 0) x += MOD;
        return *this;
    }
    constexpr bool operator < (const ModInt a) const noexcept { return x < a.x;}
    constexpr bool operator == (const ModInt a) const noexcept { return this->x == a.x;}
    constexpr bool operator != (const ModInt a) const noexcept { return !(*this == a);}
    friend istream &operator >> (istream &in, ModInt &m) {
        in >> m.x;
        if (m.x < 0) m.x += MOD;
        m.x %= MOD;
        return in;
    }
    friend ostream &operator << (ostream &out, const ModInt &p) { return out << p.x;}
    constexpr ModInt pow(int64_t p) const {
        ModInt ret(1);
        ModInt mul(x);
        while (p > 0) {
            if (p & 1ul) ret *= mul;
            mul *= mul;
            p >>= 1ul;
        }
        return ret;
    }
};

const int64_t MOD = 998244353LL;
using mint = ModInt<MOD>;

int main() {
    int N; cin >> N;
    vector<pair<int, int>> A(N);
    for(auto &e : A) cin >> e.first >> e.second;
    sort(A.begin(), A.end());
    vector<vector<int>> G(N);
    set<pair<int, int>> st;
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> que;
    for(int i = N - 1; i >= 0; --i) {
        int x, d; tie(x, d) = A[i];
        while(!que.empty() && que.top().first < x + d) {
            G[i].push_back(que.top().second);
            que.pop();
        }
        que.emplace(x, i);
    }
    vector<bool> visited(N);
    auto dfs = [&](auto &&dfs, int cur) -> mint {
        mint res = 1;
        visited[cur] = true;
        for(auto &to : G[cur]) res *= dfs(dfs, to);
        return res + 1;
    };
    mint ans = 1;
    for(int i = 0; i < N; ++i) {
        if(!visited[i]) ans *= dfs(dfs, i);
    }
    cout << ans << '\n';
    return 0;
}


Measured memory_bytes: 18304