/**
* author: wxhtzdy
* created: 12.02.2023 12:07:23
**/
#include <bits/stdc++.h>
using namespace std;
const int N = 500500;
const int M = 8 * N;
int st[2][M];
void build(int x, int p, int l, int r, int v) {
st[x][p] = v;
if (l == r) {
return;
}
int mid = l + r >> 1;
build(x, p * 2, l, mid, v);
build(x, p * 2 + 1, mid + 1, r, v);
}
int query(int x, int p, int l, int r, int ll, int rr) {
if (l > r || l > rr || r < ll) {
return -2e9;
}
if (ll <= l && r <= rr) {
return st[x][p];
}
int mid = l + r >> 1;
return max(query(x, p * 2, l, mid, ll, rr), query(x, p * 2 + 1, mid + 1, r, ll, rr));
}
void modify(int x, int p, int l, int r, int i, int v) {
st[x][p] = max(st[x][p], v);
if (l == r) {
return;
}
int mid = l + r >> 1;
if (i <= mid) {
modify(x, p * 2, l, mid, i, v);
} else {
modify(x, p * 2 + 1, mid + 1, r, i, v);
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<int> x(n);
vector<int> e(n);
for (int i = 0; i < n; i++) {
cin >> x[i] >> e[i];
}
vector<int> order(n);
iota(order.begin(), order.end(), 0);
sort(order.begin(), order.end(), [&](int i, int j) {
return e[i] > e[j];
});
vector<int> xs;
for (int i = 0; i < n; i++) {
xs.push_back(x[i]);
}
sort(xs.begin(), xs.end());
xs.erase(unique(xs.begin(), xs.end()), xs.end());
int k = (int) xs.size();
auto GetVal = [&](int t) {
return (int) (lower_bound(xs.begin(), xs.end(), t) - xs.begin());
};
build(0, 1, 0, k - 1, -2e9);
build(1, 1, 0, k - 1, -2e9);
int ans = 0;
for (int i : order) {
// e[j] - x[j] >= e[i] - x[i], x[i] <= x[j]
// e[j] + x[j] >= x[i] + e[i], x[i] >= x[j]
int p = GetVal(x[i]);
if (query(0, 1, 0, k - 1, p, k - 1) >= e[i] - x[i]) {
continue;
}
if (query(1, 1, 0, k - 1, 0, p) >= e[i] + x[i]) {
continue;
}
ans += 1;
modify(0, 1, 0, k - 1, p, e[i] - x[i]);
modify(1, 1, 0, k - 1, p, e[i] + x[i]);
}
cout << ans << '\n';
return 0;
}
