#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 7;
vector<pair<int, int> > v, v1;
int dp[maxn];
map<long long int, int> m;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  int n, x, w, ans = 1, last = 0;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> x >> w;
    v.push_back(make_pair(x, w));
    v1.push_back(make_pair(x + w, i));
  }
  sort(v1.begin(), v1.end());
  for (int i = 1; i < n; i++) {
    int indx = v1[i].second;
    if ((v[indx].first - v[indx].second) >= v1[last].first) {
      last = i;
      ans++;
    }
  }
  cout << ans << "\n";
}
