#include <bits/stdc++.h>
using namespace std::literals::string_literals;
using i64 = std::int_fast64_t;
using std::cout;
using std::cerr;
using std::endl;
using std::cin;

template<typename T>
std::vector<T> make_v(size_t a){return std::vector<T>(a);}

template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts){
  return std::vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}

template<typename Monoid>
class segment_tree {
	using value_type = Monoid;
	using size_type = size_t;

	using binary_function = std::function<value_type(value_type, value_type)>;
	using checker = std::function<bool(value_type)>;
	
	const size_type size_;
	size_type height_;

	const value_type id;
	const binary_function bi_func;
	std::vector<value_type> data;
	
	private:
	const size_type get_height(const size_type& size) const {
		size_type height = 1;
		while(1 << height <= size) height++;
		return height;
	}
	const size_type base_size() const {
		return 1 << height_;
	}
	void meld(const size_type& index) {
		data[index] = bi_func(data[index << 1 ^ 0], data[index << 1 ^ 1]);
	}
	
	public:
	segment_tree(const size_type& size, const binary_function& bi_func, const value_type& id)
		: size_(size),
		  bi_func(bi_func),
		  id(id) {
		height_ = get_height(size);
		data.assign(base_size() << 1, id);
	}
	value_type fold(size_type left, size_type right) {
		value_type l_value = id,
				   r_value = id;

		for(left += base_size(), right += base_size();
			left < right;
			left >>= 1, right >>= 1) {
			if(left & 1)  l_value = bi_func(l_value, data[left++]);
			if(right & 1) r_value = bi_func(data[--right], r_value); 
		}
		return bi_func(std::move(l_value), std::move(r_value));
	}
	void update(size_type index, const value_type& value) {
		index += base_size();
		data[index] = bi_func(data[index], value);

		while(index >>= 1) meld(index);
	}
	void change(size_type index, const value_type& value) {
		index += base_size();
		data[index] = value;

		while(index >>= 1) meld(index);
	}
	const size_type search(const size_type & left, const checker & check) {
		value_type val = id;
		size_type k = left + base_size();
		while(true) {
			if(check(bi_func(val, data[k]))) {
				val = bi_func(val, data[k]);
				if(k & 1) {
					if((k + 1) & k) k = (k + 1) >> 1;
					else return size();
				} else {
					k = k + 1;
				}
			} else {
				if(k < base_size()) {
					k = k << 1 ^ 0;
				} else {
					return k - base_size();
				}
			}
		}
	}
	
	value_type operator[](const size_type& index) const {
		return data[index + base_size()];
	}
	const size_type size() const {
		return size_;
	}
	const bool empty() const {
		return data.empty();
	}
};

template <std::uint_fast64_t Modulus>
class modint {
	using u32 = std::uint_fast32_t;
	using u64 = std::uint_fast64_t;
	using i64 = std::int_fast64_t;
	
	public:
	u64 a;

	constexpr modint() noexcept : a(0) {}
	constexpr modint(const u64 & x) noexcept : a(x % Modulus) {}

	constexpr u64 &value() noexcept { return a; }
	constexpr const u64 &value() const noexcept { return a; }

	const modint inverse() const {
		return modint(1) / *this;
	}
	const modint pow(i64 k) const {
		return modint(*this) ^ k;
	}

	static u64 mod() { return Modulus; }

	constexpr modint & operator+=(const modint & rhs) noexcept {
		a += rhs.a;
		if (a >= Modulus) a -= Modulus;
		return *this;
	}
	constexpr modint & operator-=(const modint & rhs) noexcept {
		if (a < rhs.a) a += Modulus;
		a -= rhs.a;
		return *this;
	}
	constexpr modint & operator*=(const modint & rhs) noexcept {
		a = a * rhs.a % Modulus;
		return *this;
	}
	constexpr modint & operator/=(modint rhs) noexcept {
		u64 exp = Modulus - 2;
		while (exp) {
			if (exp % 2) (*this) *= rhs;
			
			rhs *= rhs;
			exp /= 2;
		}
		return *this;
	}
	constexpr modint & operator^=(u64 k) noexcept {
		auto b = modint(1);
		while(k) {
			if(k & 1) b = b * (*this);
			(*this) *= (*this);
			k >>= 1;
		}
		return (*this) = b;
	}
	constexpr modint & operator=(const modint & rhs) noexcept {
		a = rhs.a;
		return (*this);
	}
	constexpr modint operator+(const modint & rhs) const noexcept { return modint(*this) += rhs; }
	constexpr modint operator-(const modint & rhs) const noexcept { return modint(*this) -= rhs; }	
	constexpr modint operator*(const modint & rhs) const noexcept { return modint(*this) *= rhs; }
	constexpr modint operator/(const modint & rhs) const noexcept { return modint(*this) /= rhs; }
	constexpr modint operator^(const u64 & k) const noexcept { return modint(*this) ^= k; }
	constexpr modint operator-() const noexcept { return modint(Modulus - a); }
	constexpr modint operator++() noexcept { return (*this) = modint(*this) + 1; }
	constexpr modint operator--() noexcept { return (*this) = modint(*this) - 1; }
	const bool operator==(const modint & rhs) const noexcept { return a == rhs.a; };
	const bool operator!=(const modint & rhs) const noexcept { return a != rhs.a; };
	const bool operator<=(const modint & rhs) const noexcept { return a <= rhs.a; };
	const bool operator>=(const modint & rhs) const noexcept { return a >= rhs.a; };
	const bool operator<(const modint & rhs) const noexcept { return a < rhs.a; };
	const bool operator>(const modint & rhs) const noexcept { return a > rhs.a; };
	explicit operator bool() const { return a; }
	explicit operator u32() const { return a; }

	friend std::ostream & operator<<(std::ostream & os, const modint & p) {
		return os << p.a;
	}
	friend std::istream & operator>>(std::istream & is, modint & p) {
		u64 t;
		is >> t;
		p = modint(t);
		return is;
	}
};
using mint = modint<998244353>;

int main() {
	int n; scanf("%d", &n);
	std::vector<int> a(n), b(n);
	for(int i = 0; i < n; i++) scanf("%d%d", &a[i], &b[i]);

	std::vector<std::pair<int, int>> vec(1, {1 << 30, n});
	for(int i = 0; i < n; i++) vec.push_back({a[i], i});
	sort(begin(vec), end(vec));
	
	auto f = [&](int a, int b) { return std::max(a, b); };
	segment_tree<int> seg(n + 1, f, 0);
	for(int i = 0; i < n + 1; i++) seg.change(i, i + 1);
	for(int i = n - 1; i >= 0; i--) {
		int id = vec[i].second;
		int k = upper_bound(begin(vec), end(vec), std::make_pair(a[id] + b[id], -1)) - begin(vec);
		seg.change(i, seg.fold(i, k));
	}

	std::vector<mint> dp(n + 1); dp[0] = 1;
	for(int i = 0; i < n; i++) {
		dp[i + 1] += dp[i];
		dp[seg[i]] += dp[i];
	}

	printf("%lld\n", dp[n].value());
	return 0;
}


Measured memory_bytes: 7152