#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int long long
#define yes() cout << "YES\n"
#define no() cout << "NO\n"
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
const int inf = 1e18;
const int mod = 1e9 + 7;
const int maxn = 1e7 + 5e6;
const int mod1 = 998244353;
const int mod2 = 1e18 + 1;
const int mod3 = 1e9 + 9;
const int mod4 = 333333333;
const int mod5 = 200000;
const int mod6 = 10007;
const int k = 300;
const int w = 1e5;
const ld EPS = 1e-8;
int LOG = 30;
void solve() {
int n;
cin >> n;
vector<pair<int, int>> a(n);
for (auto& i : a) cin >> i.first >> i.second;
sort(all(a), [&](pair<int, int> a, pair<int, int> b) {
return a.second < b.second || (a.second == b.second && a.first < b.first);
});
int ans = n;
vector<int> cnt(n);
for (int i = 0; i < n; i++) {
for (int j = i + 1; j < n; j++) {
if (a[i].first >= a[j].first) {
if (a[i].first + a[i].second <= a[j].first + a[j].second) cnt[i] = 1;
} else {
if (a[i].second - a[i].first <= a[j].second - a[j].first) cnt[i] = 1;
}
// if (abs(a[i].first - a[j].first) <= a[j].second - a[i].second) cnt[i] = 1;
}
}
cout << ans - accumulate(all(cnt), 0ll) << "\n";
}
signed main() {
// cout.precision(16);
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
// cin >> t;
while (t--) {
solve();
}
}
