#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 100;
pair<int, int> a[N];
bool cmp(pair<int, int> x, pair<int, int> y) {
  if (x.second == y.second) return x.first < y.first;
  return x.second < y.second;
}
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    a[i].first = x - y;
    a[i].second = x + y;
  }
  sort(a + 1, a + n + 1, cmp);
  int last = a[1].second, ans = 1;
  for (int i = 2; i <= n; i++) {
    if (a[i].first >= last) {
      ans++;
      last = a[i].second;
    }
  }
  printf("%d\n", ans);
  return 0;
}
