#include <bits/stdc++.h>
using namespace std;
struct node {
  int l, r;
} a[200012];
inline bool cmp(node x, node y) {
  return (x.r < y.r || x.r == y.r && x.l < y.l);
}
int main() {
  int n, x, y, sum, mr;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &x, &y);
    a[i].l = x - y;
    a[i].r = x + y;
  }
  sort(a + 1, a + 1 + n, cmp);
  sum = 0, mr = -2147483646;
  for (int i = 1; i <= n; i++)
    if (a[i].l >= mr) sum++, mr = a[i].r;
  return printf("%d\n", sum), 0;
}
