#include <iostream>
#include <iomanip>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <stack>
#include <queue>
#include <bitset>
#include <numeric>
#include <cassert>
#include <memory>
#ifdef DEBUG
#include "./snippet/debug.hpp"
#include "./snippet/Timer.hpp"
#include "./snippet/sample.hpp"
#else
#define dump(...)
#endif

/* (=＾o＾=) */
#define int ll

/* macro */
#define FOR(i, b, e) for(ll i = (ll)(b); i < (ll)(e); ++i)
#define RFOR(i, b, e) for(ll i = (ll)(e-1); i >= (ll)(b); --i)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define REPC(x,c) for(const auto& x:(c))
#define REPI2(it,b,e) for(auto it = (b); it != (e); ++it)
#define REPI(it,c) REPI2(it, (c).begin(), (c).end())
#define RREPI(it,c) REPI2(it, (c).rbegin(), (c).rend())
#define REPI_ERACE2(it, b, e) for(auto it = (b); it != (e);)
#define REPI_ERACE(it, c) REPI_ERACE2(it, (c).begin(), (c).end())
#define ALL(x) (x).begin(),(x).end()
#define cauto const auto&
/* macro func */
template<class T>
inline auto sort(T & t) { std::sort(ALL(t)); }
template<class T>
inline auto rsort(T& t) { std::sort((t).rbegin(), (t).rend()); }
template<class T>
inline auto unique(T& t) { (t).erase(unique((t).begin(), (t).end()), (t).end()); }
template<class T, class S>
inline auto chmax(T& t, const S& s) { if (s > t) { t = s; return true; } return false; }
template<class T, class S>
inline auto chmin(T& t, const S& s) { if (s < t) { t = s; return true; } return false; }
inline auto BR() { std::cout << "\n"; }

/* type define */
using ll = long long;
using PAIR = std::pair<ll, ll>;
using VS = std::vector<std::string>;
using VL = std::vector<long long>;
using VVL = std::vector<VL>;
using VVVL = std::vector<VVL>;
using VD = std::vector<double>;
template<class T>
using V = std::vector<T>;

/* using std */
using std::cout;
constexpr char endl = '\n';
using std::cin;
using std::pair;
using std::string;
using std::stack;
using std::queue;
using std::vector;
using std::list;
using std::map;
using std::unordered_map;
using std::multimap;
using std::unordered_multimap;
using std::set;
using std::unordered_set;
using std::unordered_multiset;
using std::multiset;
using std::bitset;
using std::priority_queue;

/* constant value */
constexpr ll MOD = 1000000007;
//constexpr ll MOD = 998244353;

/* Initial processing  */
struct Preprocessing { Preprocessing() { std::cin.tie(0); std::ios::sync_with_stdio(0); }; }_Preprocessing;

/* Remove the source of the bug */
constexpr signed pow(signed, signed) { return -1; }

/* define hash */
namespace std { template <>	class hash<std::pair<ll, ll>> { public:	size_t operator()(const std::pair<ll, ll>& x) const { return hash<ll>()(1000000000 * x.first + x.second); } }; }

/* input */
template<class T> std::istream& operator >> (std::istream& is, vector<T>& vec) { for (T& x : vec) is >> x; return is; }

//=============================================================================================


auto solve(ll n, const V<PAIR> & v_) {
	V<PAIR> v; v.reserve(n);
	REPC(p, v_) {
		v.emplace_back(p.first + p.second - 1, p.first);
	}
	sort(v);

	ll mx = -1e15;
	ll ans = 0;
	REPC(p, v) {
		ll l = p.second - (p.first - p.second);
		if (l > mx) {
			++ans;
			mx = p.first;
		}
	}
	return ans;
}

auto solve2(ll n, const V<PAIR> & v_) {
	// [r,l]
	V<PAIR> v; v.reserve(n);
	REPC(p, v_) {
		v.emplace_back(p.first + p.second, p.first - p.second);
	}
	sort(v);
	ll ans = 0;
	ll r = -1e15;
	REPC(p, v) {
		if (p.second >= r) {
			++ans;
			r = p.first;
		}
	}
	return ans;
}

auto solve_c(ll n, const V<PAIR> & v) {

	ll ans = 0;
	REP(i, (1LL << n)) {
		VL t(100);
		ll cnt = 0;
		REP(j, n)if ((i >> j) & 1) {
			FOR(k, std::max(0LL, v[j].first - v[j].second + 1), v[j].first + v[j].second) {
				++t[k];
			};
			++cnt;
		}
		bool ok = true;
		REPC(x, t)if (x > 1) { ok = false; break; }
		if (ok) { chmax(ans, cnt); }
	}
	return ans;
}
signed main() {
	/**/
	ll n;
	cin >> n;
	V<PAIR> v; v.reserve(n);
	REP(_, n) {
		ll x, l;
		cin >> x >> l;
		v.emplace_back(x, l);
	}

	auto ans = solve2(n, v);
	cout << ans << endl;

	//auto ans_c = solve_c(n, v);
	//cout << ans_c << endl;
	/*/
	auto gen = Sample::SampleGenerator();
	REP(_, 100) {
		auto [n] = gen.generate(PAIR{3,10});
		auto [v1, v2] = gen.generate(V<PAIR>(n, {1,50}), V<PAIR>(n, {3,10}));
		V<PAIR> v; v.reserve(n);
		REP(i, n) { v.emplace_back(v1[i], v2[i]); }
		auto ans = solve2(n, v);
		auto ans_c = solve_c(n, v);

		if (ans != ans_c) {
			cout << n << endl;
			REPC(p, v) {
				cout << p.first << " " << p.second << endl;
			}
			dump(ans, ans_c);
			return 0;
		}
	}
	/**/
}

Measured memory_bytes: 3328