#include <bits/stdc++.h>
const int N = 2e5 + 5;
int n, l[N], r[N], a[N];
bool cmp(int x, int y) { return r[x] == r[y] ? l[x] < l[y] : r[x] < r[y]; }
int main() {
  scanf("%d", &n);
  int u, v;
  for (int i = 1; i <= n; ++i) {
    scanf("%d", &u), scanf("%d", &v);
    l[i] = u - v, r[i] = u + v, a[i] = i;
  }
  std::sort(a + 1, a + n + 1, cmp);
  int ans = 0, maxx = -2e9;
  for (int i = 1; i <= n; ++i)
    if (maxx <= l[a[i]]) ++ans, maxx = r[a[i]];
  printf("%d\n", ans);
  return 0;
}
