#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;
struct segTree {
vector<int> t;
int n;
segTree(int x) {
n = x;
t.resize(4 * n, -inf);
}
void upd(int v, int l, int r, int idx, int val) {
if (r - l == 1) {
t[v] = val;
return;
}
int m = (l + r) / 2;
if (idx < m) upd(2 * v, l, m, idx, val);
else upd(2 * v + 1, m, r, idx, val);
t[v] = max(t[2 * v], t[2 * v + 1]);
}
void upd(int idx, int val) {
upd(1, 0, n, idx, val);
}
int get(int v, int l, int r, int ql, int qr) {
if (l >= qr || r <= ql) return -inf;
if (ql <= l && r <= qr) return t[v];
int m = (l + r) / 2;
return max(get(2 * v, l, m, ql, qr), get(2 * v + 1, m, r, ql, qr));
}
int get(int ql, int qr) {
return get(1, 0, n, ql, qr);
}
};
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);
});
vector<int> b;
for (int i = 0; i < n; i++) b.push_back(a[i].first);
sort(all(b));
b.resize(unique(all(b)) - b.begin());
for (int i = 0; i < n; i++) a[i].first = lower_bound(all(b), a[i].first) - b.begin();
segTree st1(n), st2(n);
int ans = n;
vector<int> cnt(n);
vector<int> cnt1(n), cnt2(n);
for (int i = n - 1; i >= 0; i--) {
int val = a[i].first;
if (b[val] + a[i].second <= st1.get(0, val + 1)) cnt[i] = 1;
if (a[i].second - b[val] <= st2.get(val + 1, n)) cnt[i] = 1;
st1.upd(val, max(b[val] + a[i].second, st1.get(val, val + 1)));
st2.upd(val, max(a[i].second - b[val], st2.get(val, val + 1)));
}
// 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;
// }
// }
// }
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();
}
}
