#include <bits/stdc++.h>
using namespace std;
#define int long long
#define vt vector
signed main() {
int n;
cin >> n;
vt<int> x(n);
vt<int> e(n);
for (int i=0 ; i<n ; i++)
cin >> x[i] >> e[i];
vector<pair<int,int>> intervals;
for (int i = 0; i < n; i++) {
intervals.push_back({x[i] - e[i], x[i] + e[i]});
}
sort(intervals.begin(), intervals.end(), [](auto &a, auto &b){
if (a.first == b.first) return a.second > b.second;
return a.first < b.first;
});
int count = 0;
int max_right = -LLONG_MAX;
for (auto [l, r] : intervals) {
if (r > max_right) {
count++;
max_right = r;
}
}
cout << count << endl;
}
