#include <bits/stdc++.h>
using namespace std;
int n;
int l[200005], r[200005], id[200005];
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 a, b;
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &a, &b);
    l[i] = a - b;
    r[i] = a + b;
    id[i] = i;
  }
  sort(id + 1, id + n + 1, cmp);
  int ans = 0, sum = -2e9;
  for (int i = 1; i <= n; i++)
    if (sum <= l[id[i]]) ++ans, sum = r[id[i]];
  printf("%d\n", ans);
  return 0;
}
