#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 100000;
const int MAX_V = 1000000000;
int N;
int X[MAX_N];
int L[MAX_N];
void input() {
  scanf("%d", &N);
  for (int i = 0; i < N; ++i) {
    scanf("%d%d", X + 1, L + 1);
  }
}
pair<int, int> ps[MAX_N];
int solve() {
  for (int i = 0; i < N; ++i) {
    ps[i] = pair<int, int>(X[i] + L[i], X[i] - L[i]);
  }
  sort(ps, ps + N);
  int cur = -MAX_V;
  int ans = 0;
  for (int i = 0; i < N; ++i) {
    if (cur <= ps[i].second) {
      ans++;
      cur = ps[i].first;
    }
  }
  return ans;
}
int main() {
  input();
  int ans = solve();
  printf("%d\n", ans);
  return 0;
}
