/*
* Author: Nonoze
* Created: Saturday 06/04/2024
*/
#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<class T> using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
#define int long long
#ifdef _IN_LOCAL
#include <bits/DebugTemplate.h>
#else
#define dbg(...) ;
#endif
#define sz(x) (int)(x.size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define endl '\n'
#define endlfl '\n' << flush
#define quit(x) {cout << x << endl; return;}
const int MOD = 1e9+7;
const ll inf = 1e18;
template<typename T> constexpr bool cmax(T &a, const T &b) { return a < b ? a = b, 1 : 0; }
template<typename T> constexpr bool cmin(T &a, const T &b) { return b < a ? a = b, 1 : 0; }
void solve();
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
int tt=1;
// cin >> tt;
while(tt--) solve();
return 0;
}
int n, k, m, q;
vector<pair<int, int>> a;
string s;
void solve() {
cin >> n;
a.clear(), a.resize(n);
for (auto &u: a) cin >> u.fi >> u.se;
sort(all(a), [&](auto a, auto b) {
int bega=a.fi-a.se, begb=b.fi-b.se;
return (bega==begb?a.fi+a.se>b.fi+b.se:bega<begb);
});
int act=-inf, ans=0;
for (auto u: a) {
if (act<u.fi+u.se) {
act=u.fi+u.se;
ans++;
}
}
cout << ans << endl;
}
