#include <bits/stdc++.h>
using namespace std;
long long N, rs, Y = -2e9;
struct my {
  long long x, y;
} A[200100];
bool comp(my a, my b) { return a.x < b.x || (a.x == b.x && a.y < b.y); }
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> N;
  for (int i = 0, x, k; i < N; i++) {
    cin >> x >> k;
    A[i].x = x - k;
    A[i].y = x + k;
  }
  sort(A, A + N, comp);
  for (int i = 0, x, k; i < N; i++) {
    if (A[i].x >= Y) {
      rs++;
      Y = A[i].y;
    } else if (A[i].y < Y)
      Y = A[i].y;
  }
  cout << rs;
}
