#include <bits/stdc++.h>
#include <fstream>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/trie_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template<class A, class B>
ostream& operator<<(ostream& o, const pair<A, B>& p) {return o << '(' << p.first << ", " << p.second << ')';}
template<size_t Index = 0, typename... Types>
ostream& printTupleElements(ostream& o, const tuple<Types...>& t) {if constexpr (Index < sizeof...(Types)){if(Index > 0){o << ", ";}o << get<Index>(t);printTupleElements<Index + 1>(o, t);}return o;}
template<typename... Types>
ostream& operator<<(ostream& o, const tuple<Types...>& t){o << "(";printTupleElements(o, t);return o << ")";}
template<class T>
auto operator<<(ostream& o, const T& x) -> decltype(x.end(), o){o << '{';bool first = true;for (const auto& e : x){if (!first){o << ", ";}o << e;first = false;} return o << '}';}
#define DEBUG
#ifdef DEBUG
#define fastio()
#define debug(x...) cerr << "[" #x "]: ", [](auto... $) {((cerr << $ << "; "), ...); }(x), cerr << '\n'
#define check(x) if (!(x)) { cerr << "Check failed: " << #x << " in line " << __LINE__ << endl; exit(1); }
#else
#define fastio() ios_base::sync_with_stdio(0); cin.tie(0);
#define debug(...)
#define check(x) 
#endif
typedef long long ll;
#define pi pair<int, int>
#define pll pair<ll, ll>
#define st first
#define nd second
#define vi vector<int>
#define vll vector<ll>
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size
constexpr int base = (1 << 19);
int baz = 1;
int tri[2 * base][2];
map<int, int>con;
void upd(int v, int x, int k) {
	v += baz;
	while(v > 0) {
		tri[v][k] = max(tri[v][k], x);
		v /= 2;
	}
}
int que(int l, int r, int k) {
	l += baz;
	r += baz;
	int ans = -2e9;
	while(l <= r) {
		if(l & 1) {
			ans = max(ans, tri[l][k]);
		}
		if(!(r & 1)) {
			ans = max(ans, tri[r][k]);
		}
		l = (l + 1) / 2;
		r = (r - 1) / 2;
	}
	return ans;
}
void solve() {
	//ifstream cin("nazwa.in");
	//ofstream cout("nazwa.out");
	int n;
	cin >> n;
	while(baz <= n) {
		baz *= 2;
	}
	for(int i = 0; i < 2 * baz; i++) {
		tri[i][0] = -2e9;
		tri[i][1] = -2e9;
	}
	vector<pi>prz;
	for(int i = 1; i <= n; i++) {
		int x, e;
		cin >> x >> e;
		con[x] = 1;
		prz.eb(e, x);
	}
	int k = 1;
	for(auto &[key, val] : con) {
		val = k++;
	}
	sort(all(prz));
	reverse(all(prz));
	int ans = 0;
	for(auto [E, x] : prz) {
		int a = que(1, con[x], 0), b = que(con[x], k, 1);
		if(que(1, con[x], 0) < E + x && que(con[x], k, 1) < E - x) {
			ans++;
		}
		upd(con[x], E + x, 0);
		upd(con[x], E - x, 1);
	}
	cout << ans << '\n';
}
int main() {
	fastio();
	int t = 1;
	//cin >> t;
	while(t--) {
		solve();
	}
}