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

typedef pair<int, int> pii;
typedef long long ll;
template<class T> using V = vector<T>;
template<class T> using VV = V<V<T>>;

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define rep(i,n) rep2(i,0,n)
#define rep2(i,m,n) for(int i=m;i<(n);i++)
#define ALL(c) (c).begin(),(c).end()

#ifdef LOCAL
#define dump(x) cerr << __LINE__ << " " << #x << " = " << (x) << endl
#else 
#define dump(x) true
#endif

constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n-1); }

template<class T, class U> bool chmax(T& t, const U& u) { if (t < u) { t = u; return 1; } return 0; }
template<class T, class U> bool chmin(T& t, const U& u) { if (t > u) { t = u; return 1; } return 0; }

template<class T, class U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
	os<<"("<<p.first<<","<<p.second<<")";
	return os;
}

template<class T>
ostream& operator<<(ostream& os, const vector<T>& v) {
	os<<"{";
	rep(i, v.size()) {
		if (i) os<<",";
		os<<v[i];
	}
	os<<"}";
	return os;
}

template <unsigned int MOD>
struct ModInt {
	using uint = unsigned int;
	using ull = unsigned long long;
	using M = ModInt;

	uint v;

	ModInt(ll _v = 0) { set_norm(_v % MOD + MOD); }
	M& set_norm(uint _v) { //[0, MOD * 2)->[0, MOD)
		v = (_v < MOD) ? _v : _v - MOD;
		return *this;
	}

	explicit operator bool() const { return v != 0; }
	M operator+(const M& a) const { return M().set_norm(v + a.v); }
	M operator-(const M& a) const { return M().set_norm(v + MOD - a.v); }
	M operator*(const M& a) const { return M().set_norm(ull(v) * a.v % MOD); }
	M operator/(const M& a) const { return *this * a.inv(); }
	M& operator+=(const M& a) { return *this = *this + a; }
	M& operator-=(const M& a) { return *this = *this - a; }
	M& operator*=(const M& a) { return *this = *this * a; }
	M& operator/=(const M& a) { return *this = *this / a; }
	M operator-() const { return M() - *this; }
	M& operator++(int) { return *this = *this + 1; }
	M& operator--(int) { return *this = *this - 1; }

	M pow(ll n) const {
		if (n < 0) return inv().pow(-n);
		M x = *this, res = 1;
		while (n) {
			if (n & 1) res *= x;
			x *= x;
			n >>= 1;
		}
		return res;
	}

	M inv() const {
		ll a = v, b = MOD, p = 1, q = 0, t;
		while (b != 0) {
			t = a / b;
			swap(a -= t * b, b);
			swap(p -= t * q, q);
		}
		return M(p);
	}

	bool operator==(const M& a) const { return v == a.v; }
	bool operator!=(const M& a) const { return v != a.v; }
	friend ostream& operator<<(ostream& os, const M& a) { return os << a.v; }
};

using Mint = ModInt<998244353>;

const int SZ = 1 << 18;

template<class T>
struct segtree {
	vector<T> dat;

	const T inf = numeric_limits<T>::lowest();

	void init() {
		dat.resize(SZ * 2);
		rep(i, SZ * 2) dat[i] = inf;
	}

	void update(int pos, T x) {
		pos += SZ - 1;
		dat[pos] = x;

		while (pos > 0) {
			pos = (pos - 1) / 2;
			dat[pos] = max(dat[pos * 2 + 1], dat[pos * 2 + 2]);
		}
	}

	T get(int a, int b, int k = 0, int l = 0, int r = SZ) {
		if (b <= l || r <= a) return inf;
		if (a <= l && r <= b) return dat[k];
		return max(get(a, b, k * 2 + 1, l, (l + r) / 2), get(a, b, k * 2 + 2, (l + r) / 2, r));
	}
};

int main() {
	int N; cin >> N;
	V<pii> vec(N);
	rep(i, N) {
		int x, d; cin >> x >> d;
		vec[i] = mp(x, d);
	}
	sort(ALL(vec));

	V<int> tor(N);
	iota(ALL(tor), 0);

	segtree<int> seg;
	seg.init();

	for (int i = N-1; i >= 0; --i) {
		int r = lower_bound(ALL(vec), mp(vec[i].fi + vec[i].se, -1)) - vec.begin();
		int v = seg.get(i, r);
		chmax(tor[i], v);
		seg.update(i, tor[i]);
	}

	V<Mint> dp(N + 1);
	dp[N] = 1;

	for (int i = N-1; i >= 0; --i) {
		int r = tor[i];
		dp[i] += dp[i+1];
		dp[i] += dp[r+1];
	}

	cout << dp[0] << endl;

	return 0;
}

Measured memory_bytes: 5376