#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 5;
int n, ans, v[N];
pair<int, int> a[N];
tuple<int, int, int> b[N], c[N];
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;
for(int i = 1;i<=n;i++) cin >> a[i].second >> a[i].first;
sort(a + 1, a + n + 1, greater<pair<int, int>>());
for(int i = 1;i<=n;i++) b[i] = {a[i].first - a[i].second, a[i].second, i}, c[i] = {a[i].first + a[i].second, a[i].second, i};
sort(b + 1, b + n + 1);
sort(c + 1, c + n + 1);
int ptr1 = 1, ptr2 = 1;
for(int i = 1;i<=n;i++){
if(v[i]) continue;
++ans;
for(int j = 1;j<=n;j++){
if((a[i].first - a[i].second >= a[j].first - a[j].second && a[j].second <= a[i].second) || (a[i].first + a[i].second >= a[j].first + a[j].second && a[i].second <= a[j].second)) v[j] = 1;
}
}
cout << ans;
}
