#include <bits/stdc++.h>
using namespace std;
const int INF = 1000000000;
const int N = 300000;
struct point {
  long long lrg;
  long long sml;
} p[N];
bool sc(const point &a, const point &b) { return a.sml < b.sml; }
long long n, cnt, x, w, k, nxt;
int main() {
  ios_base::sync_with_stdio(0);
  scanf("%I64d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%I64d%I64d", &x, &w);
    p[i].sml = x - w;
    p[i].lrg = x + w;
  }
  sort(p + 1, p + 1 + n, sc);
  k = n - 1;
  cnt = 1;
  nxt = p[n].sml;
  while (k >= 1) {
    if (nxt >= p[k].lrg) {
      nxt = p[k].sml;
      cnt++;
    }
    k--;
  }
  printf("%I64d", cnt);
  return 0;
}
