#include <bits/stdc++.h>
using namespace std;
#ifdef Ramzi
#include "debug.h"
#else
#define debug(...)
#endif
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<pair<int ,int>> p(n);
for (int i = 0; i < n; i++) {
int x, e;
cin >> x >> e;
p[i].first = x - e;
p[i].second = x + e;
}
auto com = [&](pair<int, int> &a, pair<int, int> &b) -> bool {
if (a.first != b.first) {
return a.first < b.first;
}
return a.second > b.second;
};
sort(p.begin(), p.end(), com);
int ans = 0, mx = 0;
for (auto [f, s] : p) {
if (s > mx) {
ans += 1;
mx = s;
}
}
cout << ans << "\n";
/*
* |Xi - Xj| <= Ei - Ej
* Xi - Ei <= Xj - Ej this
* Xj + Ej <= Ei + Xi this
* 4 2
* 2 3
* 3 4
* 6 5
*/
}
