#include <bits/stdc++.h>
using namespace std;
const int N = 400000;
int ans, rmax, n;
void read(int &x) { scanf("%d", &x); }
struct node {
  int l, r;
} a[N];
bool cmp(node x, node y) { return (x.r < y.r || x.r == y.r && x.l < y.l); }
int main() {
  read(n);
  for (int i = 1; i <= n; i++) {
    int x, y;
    read(x);
    read(y);
    a[i].l = x - y;
    a[i].r = x + y;
  }
  rmax = -1998244353;
  sort(a + 1, a + n + 1, cmp);
  for (int i = 1; i <= n; i++)
    if (a[i].l >= rmax) {
      ++ans;
      rmax = a[i].r;
    }
  printf("%d\n", ans);
}
