#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n, i, j, k, l;
  cin >> n;
  vector<pair<long long, long long> > arr(n);
  map<long long, long long> ind;
  for (i = 0; i < n; i++) {
    cin >> arr[i].first >> arr[i].second;
    ind[arr[i].first] = i;
  }
  sort(arr.begin(), arr.end());
  set<pair<long long, long long> > s;
  set<pair<long long, long long> >::iterator it;
  long long prevx = arr[0].first;
  long long prevw = arr[0].second;
  long long ans = 1;
  long long dp[n + 1];
  dp[1] = 1;
  for (i = 2; i <= n; i++) {
    dp[i] = dp[i - 1];
    long long x = arr[i - 1].first, y = arr[i - 1].second;
    if (x - prevx >= prevw + y) {
      prevx = x;
      prevw = y;
      dp[i]++;
    } else if (x + y <= prevx + prevw) {
      prevx = x;
      prevw = y;
    }
  }
  cout << dp[n] << "\n";
  return 0;
}
