// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
using namespace std;
// #define int long long
#define endl "\n"
#define fi first
#define se second
const int M=1e9+7;
const int inf = 1e9;
const int LOG=20;
const int N=2e5+5;
int n , m , c , w , k , t=1 , q=1 , x , y , z , l , r;
void solve()
{
cin >> n;
vector<pair<int,int>>a(n),b(n);
for (int i=0;i<n;i++){
cin >> a[i].fi >> a[i].se;
b[i]={a[i].se,a[i].fi};
}
map<int,int>vi;
sort(a.begin(),a.end());
sort(b.rbegin(),b.rend());
c=0;
set<pair<int,int>>l;
l.insert({0,0});
l.insert({1e9+1,0});
for (int i=0;i<n;i++){
x=b[i].se;
y=b[i].fi;
pair<int,int>h1,h2;
for (auto j:l){
if (h1.fi<=x and j.fi>x){
h2=j;
break;
}
h1=j;
}
if (abs(x-h1.fi)<=h1.se-y or abs(x-h2.fi)<=h2.se-y){
continue;
}
c++;
l.insert({x,y});
}
cout << c << endl;
}
signed main()
{
ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE
cin.tie(0), cout.tie(0);//DO NOT USE IN INTERACTIVE
cout << fixed << setprecision(9);
srand(time(0));
// int t=1;
// cin >> t;
for (int _=1;_<=t;_++){
solve();
q++;
}
}
