#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define f0r(i, n) for (auto i = 0; i < (n); ++i)
#define fnr(i, n, k) for (auto i = (n); i < (k); ++i)
#define all(v) (v).begin(), (v).end()
#define pb push_back
#define F first
#define S second
#define ctn(x) cout << x << '\n'
#define forl(a, l) for (auto a : l)
#define ctl(l) for (auto &a : (l)) cout << a << ' '; cout << '\n';
#define lb(v, x) (lower_bound(all(v), x) - begin(v))
#define ub(v, x) (upper_bound(all(v), x) - begin(v))
#define pq priority_queue
template <class T>
using V = vector<T>;
using ll = long long;
using vi = V<int>;
using vl = V<ll>;
using pi = pair<int, int>;
using ti = tuple<int, int, int>;
using Adj = V<vi>;
using vvi = V<vi>;
struct ST {
vi tr;
int N;
ST(int n) {
for (N=1; N<n; N*=2);
tr.assign(2*N, 2e9);
}
#define m (l+r)/2
int query(int ql, int qr, int v, int l, int r) {
if (qr < l || r < ql) return 2e9;
if (ql <= l && r <= qr) return tr[v];
return min(query(ql, qr, 2*v, l, m), query(ql, qr, 2*v+1, m+1, r));
}
void upd(int q, int x, int v, int l, int r) {
if (q < l || r < q) return;
if (l == r) {
tr[v] = min(tr[v], x);
return;
}
upd(q, x, 2*v, l, m);
upd(q, x, 2*v+1, m+1, r);
tr[v] = min(tr[2*v], tr[2*v+1]);
}
#undef m
int query(int ql, int qr) { return query(ql, qr, 1, 0, N-1); }
void upd(int q, int x) { upd(q, x, 1, 0, N-1); }
};
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int N;
cin >> N;
V<pi> ppl(N);
vi xs;
for (auto &[e, x]: ppl) {
cin >> x >> e;
xs.pb(x);
}
sort(all(xs));
xs.erase(unique(all(xs)), end(xs));
sort(all(ppl), greater<>());
ST st1(xs.size()), st2(xs.size());
int cnt = 0;
for (auto &[e, x]: ppl) {
int i = lower_bound(all(xs), x) - begin(xs);
if (st1.query(i, xs.size()-1) <= x - e || st2.query(0, i) <= -(e + x)) continue;
++cnt;
st1.upd(i, x - e);
st2.upd(i, -e -x);
}
ctn(cnt);
}
