#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
int n, l[N], r[N], id[N];
bool cmp(int x, int y) { return r[x] == r[y] ? l[x] < l[y] : r[x] < r[y]; }
int main() {
  cin >> n;
  for (int x, w, i = 1; i <= n; ++i) {
    cin >> x >> w;
    l[i] = x - w, r[i] = x + w, id[i] = i;
  }
  sort(id + 1, id + n + 1, cmp);
  int ans = 0, las = -2e9;
  for (int i = 1; i <= n; ++i)
    if (las <= l[id[i]]) ++ans, las = r[id[i]];
  cout << ans;
  return 0;
}
