#include <bits/stdc++.h>
using namespace std;
struct node {
  int l, r;
  node(int l = 0, int r = 0) : l(l), r(r) {}
  bool operator<(const node& nd) const {
    if (r != nd.r) return r < nd.r;
    return l < nd.l;
  }
};
int n;
node a[200003];
inline void read(int& x) {
  x = 0;
  char c = getchar();
  while (!isdigit(c)) c = getchar();
  while (isdigit(c)) {
    x = (x << 3) + (x << 1) + c - '0';
    c = getchar();
  }
}
int main() {
  int l, r, n, x, w, ans = 0;
  read(n);
  for (int i = 1; i <= n; ++i) {
    read(x), read(w);
    a[i] = node(x - w, x + w);
  }
  sort(a + 1, a + 1 + n);
  r = -0x3f3f3f3f;
  for (int i = 1; i <= n; ++i) {
    if (a[i].l < r) continue;
    ++ans;
    r = a[i].r;
  }
  printf("%d", ans);
  return 0;
}
