#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tt;
#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())
struct IT {
vector<int> tr;
IT (int sz) : tr(4 * sz, INT_MIN) {}
void update (int pos, int val, int k, int l, int r) {
if (pos < l || r < pos) return;
if (l == r) {
tr[k] = val;
return;
}
int mid = (l + r) >> 1;
update(pos, val, 2 * k, l, mid);
update(pos, val, 2 * k + 1, mid + 1, r);
tr[k] = max(tr[2 * k], tr[2 * k + 1]);
}
int walk (int k, int l, int r, int ub) {
if (l == r) return (tr[k] <= ub ? l : INT_MAX);
int mid = (l + r) >> 1;
if (tr[2 * k + 1] <= ub)
return min(walk(2 * k, l, mid, ub), mid + 1);
return walk(2 * k + 1, mid + 1, r, ub);
}
};
struct simpleIT {
vector<int> tr;
simpleIT (int sz) : tr(4 * sz, INT_MAX) {}
void update (int pos, int val, int k, int l, int r) {
if (pos < l || r < pos) return;
if (l == r) {
tr[k] = min(tr[k], val);
return;
}
int mid = (l + r) >> 1;
update(pos, val, 2 * k, l, mid);
update(pos, val, 2 * k + 1, mid + 1, r);
tr[k] = min(tr[2 * k], tr[2 * k + 1]);
}
int query (int a, int b, int k, int l, int r) {
if (b < l || r < a) return INT_MAX;
if (a <= l && r <= b) return tr[k];
int mid = (l + r) >> 1;
return min(query(a, b, 2 * k, l, mid), query(a, b, 2 * k + 1, mid + 1, r));
}
};
const int mn = 5e5 + 5;
struct resident {
int X, E;
resident() : X(0), E(0) {}
resident (int _x, int _e) : X(_x), E(_e) {}
friend istream& operator >> (istream &inp, resident &r) {
inp >> r.X >> r.E;
return inp;
}
bool operator < (const resident &o) const {
//if (E == o.E) return X < o.X;
//return E < o.E;
return max(E + X, E - X) < max(o.E + o.X, o.E - o.X);
}
} res[mn];
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
int n; cin >> n;
for (int i = 1; i <= n; i++) cin >> res[i];
sort(res + 1, res + 1 + n);
/*cout << "after sort\n";
for (int i = 1; i <= n; i++) {
cout << res[i].X << " " << res[i].E << "\n";
}*/
simpleIT dp(n + 1); IT trSum(n), trDif(n);
dp.update(0, 0, 1, 0, n);
for (int i = 1; i <= n; i++) {
int lb = max(trSum.walk(1, 1, n, res[i].E + res[i].X), trDif.walk(1, 1, n, res[i].E - res[i].X));
int cur = dp.query(lb - 1, i - 1, 1, 0, n) + 1;
trSum.update(i, res[i].E + res[i].X, 1, 1, n);
trDif.update(i, res[i].E - res[i].X, 1, 1, n);
dp.update(i, cur, 1, 0, n);
//cout << "dp " << i << ": " << cur << "\n";
}
cout << dp.query(n, n, 1, 0, n);
return 0;
}
