/* imports all std modules {{{*/
import
  std.algorithm,
  std.array,
  std.ascii,
  std.base64,
  std.bigint,
  std.bitmanip,
  std.compiler,
  std.complex,
  std.concurrency,
  std.container,
  std.conv,
  std.csv,
  std.datetime,
  std.demangle,
  std.encoding,
  std.exception,
  std.file,
  std.format,
  std.functional,
  std.getopt,
  std.json,
  std.math,
  std.mathspecial,
  std.meta,
  std.mmfile,
  std.net.curl,
  std.net.isemail,
  std.numeric,
  std.parallelism,
  std.path,
  std.process,
  std.random,
  std.range,
  std.regex,
  std.signals,
  std.socket,
  std.stdint,
  std.stdio,
  std.string,
  std.system,
  std.traits,
  std.typecons,
  std.uni,
  std.uri,
  std.utf,
  std.uuid,
  std.variant,
  std.zip,
  std.zlib;
/*}}}*/

/* libnum {{{*/
void amax(N, Args...)(ref N x, Args y) {
  x = x.max(y);
}
void amin(N, Args...)(ref N x, Args y) {
  x = x.min(y);
}
auto maxE(R)(R r) if (isInputRange!R) {
  ElementType!R x = r.front;
  r.popFront();
  foreach (y; r) x.amax(y);
  return x;
}
auto minE(R)(R r) if (isInputRange!R) {
  ElementType!R x = r.front;
  r.popFront();
  foreach (y; r) x.amin(y);
  return x;
}
/*}}}*/


/+---test
4
2 4
4 3
9 3
100 5
---+/
/+---test
2
8 20
1 10
---+/
/+---test
5
10 1
2 1
4 1
6 1
8 1
---+/

void main(string[] args) {
  const N = readln.chomp.to!long;

  alias Pair = Tuple!(long, "l", long, "r");
  auto pairs = new Pair[N];
  foreach (ref pair; pairs) {
    readf(" %d %d ", &pair.l, &pair.r);
    pair.l -= pair.r;
    pair.r  = pair.l + pair.r*2;
  }
  pairs.sort!"a.l < b.l";

  long ans;
  long r = long.min;
  foreach (p; pairs) {
    if (p.l < r) continue;
    ++ans;
    r = pairs.filter!(x => x.l >= p.l && x.r <= p.r).map!"a.r".minE;
  }
  ans.writeln;
}
