#include <bits/stdc++.h>
using namespace std;
const int sz = 100010;
int x[sz], h[sz];
int main() {
  int n;
  cin >> n;
  if (n == 1) {
    cout << 1;
    return 0;
  }
  int ans = 2;
  for (int i = 0; i < n; ++i) {
    cin >> x[i] >> h[i];
  }
  int left = x[0];
  for (int i = 1; i < n - 1; ++i) {
    if (left < (x[i] - h[i])) {
      ++ans;
      left = x[i];
    } else if ((x[i] + h[i]) < x[i + 1]) {
      ++ans;
      left = x[i] + h[i];
    } else {
      left = x[i];
    }
  }
  cout << ans;
  return 0;
}
