#include <bits/stdc++.h>
#define int long long
using namespace std;
vector<pair<int, int> > vec;
vector<int> seg, iL, iR, jL, jR;
int a, b, num=1000000000;
void create()
{
seg.push_back(0);
iL.push_back(0);
iR.push_back(0);
jL.push_back(0);
jR.push_back(0);
}
void upd2(int i, int l, int r)
{
//cout << "upd2 " << i << ' ' << l << ' ' << r << '\n';
if (l==r)
{
seg[i]++;
return;
}
int mid=(l+r)/2;
if (b<=mid)
{
if (!jL[i])
{
jL[i]=seg.size();
create();
}
upd2(jL[i], l, mid);
}
else
{
if (!jR[i])
{
jR[i]=seg.size();
create();
}
upd2(jR[i], mid+1, r);
}
seg[i]=seg[jL[i]]+seg[jR[i]];
}
void upd1(int i, int l, int r)
{
//cout << "upd1 " << i << ' ' << l << ' ' << r << '\n';
upd2(i, 1, num*2);
if (l==r)
return;
int mid=(l+r)/2;
if (a<=mid)
{
if (!iL[i])
{
iL[i]=seg.size();
create();
}
upd1(iL[i], l, mid);
}
else
{
if (!iR[i])
{
iR[i]=seg.size();
create();
}
upd1(iR[i], mid+1, r);
}
}
int qry2(int i, int l, int r)
{
//cout << "qry2 " << i << ' ' << l << ' ' << r << '\n';
if (r<=b)
return seg[i];
int mid=(l+r)/2, res=jL[i]?qry2(jL[i], l, mid):0;
if (mid<b)
res+=jR[i]?qry2(jR[i], mid+1, r):0;
return res;
}
int qry1(int i, int l, int r)
{
//cout << "qry1 " << i << ' ' << l << ' ' << r << '\n';
if (r<=a)
return qry2(i, 1, num*2);
int mid=(l+r)/2, res=iL[i]?qry1(iL[i], l, mid):0;
if (mid<a)
res+=iR[i]?qry1(iR[i], mid+1, r):0;
return res;
}
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
create();
create();
int n, cnt=0;
cin >> n;
for (int i=0; i<n; i++)
{
int x, y;
cin >> x >> y;
vec.push_back({y, x});
}
sort(vec.begin(), vec.end(), greater<pair<int, int> >());
for (int i=0; i<n; i++)
{
int y=vec[i].first, x=vec[i].second;
a=-x-y+num*2+1, b=x-y+num;
if (!qry1(1, 1, num*2))
{
upd1(1, 1, num*2);
cnt++;
}
}
cout << cnt;
}
