#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e6 + 25;
const ll inf = 1e16;
#define mid ((l + r) >> 1)
#define tl (node << 1)
#define tr (node << 1 | 1)
struct SegmentTree1 {
pair <ll, ll> tree[MAXN << 1];
void update (int l, int r, int a, ll b, int node) {
if (l > a || r < a) return;
if (l == r) {
tree[node] = {b, l};
return;
}
update(l, mid, a, b, tl); update(mid + 1, r, a, b, tr);
tree[node] = max(tree[tl], tree[tr]);
}
pair <ll, ll> get (int l, int r, int a, int b, int node) {
if (l > b || r < a) return {-inf, 0};
if (l >= a && r <= b) return tree[node];
return max(get(l, mid, a, b, tl), get(mid + 1, r, a, b, tr));
}
} cur1;
struct SegmentTree2 {
pair <ll, ll> tree[MAXN << 1];
void update (int l, int r, int a, ll b, int node) {
if (l > a || r < a) return;
if (l == r) {
tree[node] = {b, l};
return;
}
update(l, mid, a, b, tl); update(mid + 1, r, a, b, tr);
tree[node] = min(tree[tl], tree[tr]);
}
pair <ll, ll> get (int l, int r, int a, int b, int node) {
if (l > b || r < a) return {inf, 0};
if (l >= a && r <= b) return tree[node];
return min(get(l, mid, a, b, tl), get(mid + 1, r, a, b, tr));
}
} cur2;
array <ll, 2> a[MAXN];
int n;
bool vis[MAXN];
vector <int> topo;
int f[MAXN], g[MAXN];
void dfs (int pos) {
vis[pos] = 1;
cur1.update(1, n, pos, -inf, 1);
cur2.update(1, n, pos, inf, 1);
while (true) {
auto x = cur1.get(1, n, 1, f[pos], 1);
if (x.first < a[pos][0] - a[pos][1]) {
break;
}
dfs(x.second);
}
while (true) {
auto x = cur2.get(1, n, g[pos], n, 1);
if (x.first > a[pos][0] + a[pos][1]) {
break;
}
dfs(x.second);
}
topo.push_back(pos);
}
int comp[MAXN];
void dfs2 (int pos, int c) {
comp[pos] = c; vis[pos] = 1;
cur1.update(1, n, pos, -inf, 1);
cur2.update(1, n, pos, inf, 1);
while (true) {
auto x = cur1.get(1, n, 1, f[pos], 1);
if (x.first < a[pos][0] + a[pos][1]) {
break;
}
dfs2(x.second, c);
}
while (true) {
auto x = cur2.get(1, n, g[pos], n, 1);
if (x.first > a[pos][0] - a[pos][1]) {
break;
}
dfs2(x.second, c);
}
}
vector <int> occ[MAXN];
void solve () {
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> a[i][0] >> a[i][1];
}
sort(a + 1, a + n + 1);
for (int i = 1; i <= n; i++) {
int l = 1, r = n, ans = -1;
while (l <= r) {
if (a[mid][0] >= a[i][0]) {
ans = mid; r = mid - 1;
} else {
l = mid + 1;
}
}
g[i] = ans;
l = 1, r = n, ans = -1;
while (l <= r) {
if (a[mid][0] <= a[i][0]) {
ans = mid; l = mid + 1;
} else {
r = mid - 1;
}
}
f[i] = ans;
}
/* for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
if (i == j) continue;
if (abs(a[i][0] - a[j][0]) <= a[i][1] - a[j][1]) {
cout << i << " " << j << '\n';
}
}
}*/
for (int i = 1; i <= n; i++) {
cur1.update(1, n, i, a[i][0] - a[i][1], 1);
cur2.update(1, n, i, a[i][0] + a[i][1], 1);
}
for (int i = 1; i <= n; i++) {
if (!vis[i]) {
dfs(i);
}
}
reverse(topo.begin(), topo.end());
memset(vis, 0, sizeof(vis));
for (int i = 1; i <= n; i++) {
cur1.update(1, n, i, a[i][0] + a[i][1], 1);
cur2.update(1, n, i, a[i][0] - a[i][1], 1);
}
int cnt = 0;
for (auto i : topo) {
if (!vis[i]) {
dfs2(i, ++cnt);
}
}
for (int i = 1; i <= n; i++) {
occ[comp[i]].push_back(i);
}
for (int i = 1; i <= n; i++) {
cur1.update(1, n, i, a[i][0] + a[i][1], 1);
cur2.update(1, n, i, a[i][0] - a[i][1], 1);
}
int ans = 0;
for (int i = 1; i <= cnt; i++) {
for (auto j : occ[i]) {
cur1.update(1, n, j, -inf, 1);
cur2.update(1, n, j, inf, 1);
}
bool flag = 0;
for (auto j : occ[i]) {
auto x = cur1.get(1, n, 1, f[j], 1);
if (x.first >= a[j][0] + a[j][1]) {
flag = 1; break;
}
auto y = cur2.get(1, n, g[j], n, 1);
if (y.first <= a[j][0] - a[j][1]) {
flag = 1; break;
}
}
if (!flag) {
ans++;
}
for (auto j : occ[i]) {
cur1.update(1, n, j, a[j][0] + a[j][1], 1);
cur2.update(1, n, j, a[j][0] - a[j][1], 1);
}
}
cout << ans << '\n';
}
signed main () {
ios::sync_with_stdio(0); cin.tie(0);
int tc = 1; //cin >> tc;
while (tc--) solve();
}
