#include<bits/stdc++.h>
using namespace std;
#define int long long int
#define pii pair<int,int>
#define vi vector<int>
#define si set<int>
#define pb push_back
int32_t main() {
ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
int n; cin >> n;
pii arr[n];
for (int i=0;i<n;i++) {
int a, b; cin >> a >> b;
arr[i] = {b - a, b + a};
}
sort(arr,arr+n);
stack<pii> s;
for (int i=0;i<n;i++) {
auto cur = arr[i];
while (s.size() && s.top().first <= arr[i].first && s.top().second <= arr[i].second) {
s.pop();
}
s.push(cur);
}
cout << s.size();
return 0;
}
