#include<bits/stdc++.h>
#define IOS ios_base::sync_with_stdio(false);cin.tie();cout.tie();
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int long long
#define pq priority_queue
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define pb push_back
#define pp pop_back
#define F first
#define S second
using namespace std;
void solve () {
int n;
cin >> n;
vector<pair<int, int>> a(n);
for (int i = 0; i < n; i++) {
int x, y;
cin >> x >> y;
a[i] = {y - x, y + x};
}
sort(rall(a));
int ans = 0, pre = INT_MIN;
for (auto i: a) {
ans += i.S > pre;
pre = max(pre, i.S);
}
cout << ans << "\n";
}
signed main() {IOS solve(); return 0;}
