#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#pragma GCC optimize("inline")
#include <bits/stdc++.h>
using namespace std;
#define kien long long
#define pb push_back
#define FOR(i, a, b) for (int i = a;i <= b; i++)
#define FORD(i, a, b) for (int i = a;i >= b; i--)
#define pii pair<int, int>
#define dembit(a) __builtin_popcountll(a)
#define task "kien"
#define fin(x) freopen(x".inp","r",stdin)
#define fou(x) freopen(x".out","w",stdout)
#define debug(x) cout << x << " ";
#define down cout << "\n"
const kien MOD = 1e9 + 7;
const int NTEST = 100;
const int Million = 1e6 + 5;
const int MXN = 5e5 + 5;
mt19937 rd(chrono::high_resolution_clock::now().time_since_epoch().count());
kien rand(kien l, kien r) {
assert(l <= r);
return uniform_int_distribution<kien>(l, r)(rd);
}
kien n, k, m, dem, vis[MXN + 5], u, v;
pii a[1000000];
kien maxx, minn, vtr, l, r, ans;
pii dp[MXN];
//void sub2() {
// ans = MOD;
// FOR (mask, 1, (1 << n) - 1) {
// kien num = dembit(mask);
// FOR (i, 1, n) {
// if ((mask >> i) & 1) {
// vis[i] = 1;
// FOR (j, 1, n) {
// if (abs(a[i].first - a[j].second) <= a[i].second - a[j].second) {
// vis[j] = 1;
// }
// }
// }
// }
//
// bool ktr = true;
// FOR (i, 1, n) {
// if (!vis[i]) {ktr = false; break;}
// }
// if (ktr) ans = min(ans, num);
// }
// cout << ans;
//}
bool cmp (pii x, pii y) {
if (x.first == y.first) return x.second > y.second;
return x.first < y.first;
}
void solve() {
cin >> n;
FOR (i, 1, n) {
cin >> a[i].first >> a[i].second;
dp[i] = {a[i].first - a[i].second, a[i].first + a[i].second};
}
sort (dp + 1, dp + 1 + n, cmp);
maxx = 0;
FOR (i, 1, n) {
if (dp[i].second > maxx) {
ans++;
maxx = dp[i].second;
}
}
cout << ans;
}
main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
if (fopen(task".inp", "r")) {
fin(task); fou(task);
}
int t = 1; //cin >> t;
while(t--) solve();
cerr << "\n" << 1.0 * clock() / CLOCKS_PER_SEC << "s ";
}