import std.stdio, std.array, std.string, std.conv, std.algorithm;
import std.typecons, std.range, std.random, std.math, std.container;
import std.numeric, std.bigint, core.bitop, core.stdc.stdio;

void main() {
    auto N = readln.chomp.to!int;
    auto A = iota(N).map!(_ => readln.split.map!(to!long).array).array;
    A.sort!"a[0] < b[0]";

    int ans = N;
    long mx = -(1L<<59);

    foreach (i; 0..N) {
        auto x = A[i][0];
        auto l = A[i][1];
        if (i == 0) {
            mx = x + l;
        } else if (x - l < mx) {
            ans -= 1;
            mx = min(mx, x + l);
        }
    }

    ans.writeln;
}