#include <bits/stdc++.h>
int main() {
  long n;
  scanf("%ld\n", &n);
  std::vector<long> x(n);
  std::vector<long> h(n);
  for (int p = 0; p < n; p++) {
    scanf("%ld %ld\n", &x[p], &h[p]);
  }
  long count = (n == 1) ? 1 : 2;
  for (int p = 1; p < n - 1; p++) {
    if (x[p] - x[p - 1] > h[p]) {
      ++count;
    } else if (x[p + 1] - x[p] > h[p]) {
      ++count;
      x[p] += h[p];
    }
  }
  printf("%ld\n", count);
  return 0;
}
