#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;
//https://pastebin.com/LckN30bC
// keep values of x + e, x - e; sort by left and then right
int n;
bool compare(const pair<int, int> &a, const pair<int, int> &b) {
if (a.first != b.first) {
return a.first < b.first;
}
return a.second > b.second; // 1 4, 1 3, 1 2
}
int main() {
cin >> n;
vector<pair<int, int>> range(n);
int x, e;
for (int i = 0; i < n; i++) {
cin >> x >> e;
range[i].first = x - e;
range[i].second = x + e;
}
sort(range.begin(), range.end(), compare);
int maximum = -1;
int answer = 0;
for (int i = 0; i < n; i++) {
if (maximum < range[i].second) {
answer++;
maximum = range[i].second;
}
}
cout << answer;
}
