#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
typedef pair<int,int> pi;
typedef pair<ll,ll> pill;
typedef vector <int> vi;
typedef vector <pi> vpi;
typedef pair<pi, ll> pii;
typedef set <ll> si;
typedef long double ld;
#define f first
#define s second
#define mp make_pair
#define FOR(i,s,e) for(int i=s;i<=int(e);++i)
#define DEC(i,s,e) for(int i=s;i>=int(e);--i)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lbd(x, y) lower_bound(all(x), y)
#define ubd(x, y) upper_bound(all(x), y)
#define aFOR(i,x) for (auto i: x)
#define mem(x,i) memset(x,i,sizeof x)
#define fast ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define INF (ll)1e18
#define MOD 1000000007
typedef pair <vi, int> pvi;
typedef pair <int,pi> ipi;
typedef vector <pii> vpii;
typedef pair <pi,pi> pipi;
#define maxn 500010
int N;
int discX[maxn],E[maxn],A[maxn];
pi X[maxn]; vi v;
struct node{
int s,e,m;
pi val1,val2;
node *l=nullptr,*r=nullptr;
node(int ss,int ee){
s = ss; e = ee; m = (s + e) / 2;
if (s != e){
l = new node(s,m); r = new node(m+1,e);
val1 = min(l->val1, r->val1);
val2 = min(l->val2, r->val2);
}else{
val1 = pi(A[s] - v[s-1],s);
val2 = pi(A[s] + v[s-1],s);
}
}
void upd(int p){
if (s == e){
val1 = val2 = pi(INF,INF); return;
}else if (p > m) r->upd(p);
else l->upd(p);
val1 = min(l->val1, r->val1);
val2 = min(l->val2, r->val2);
}
pi qry(int a,int b,int t){
if (a > b) return pi(INF,INF);
if (a <= s && e <= b) return (t == 1 ? val1 : val2);
else if (a > e || s > b) return pi(INF,INF);
else return min(l->qry(a,b,t), r->qry(a,b,t));
}
}*root;
int32_t main(){
fast;
cin >> N;
FOR(i,1,N) cin >> X[i].f >> X[i].s;
sort(X+1,X+N+1);
FOR(i,1,N) v.pb(X[i].f);
v.erase(unique(all(v)), v.end());
FOR(i,1,N){
discX[i] = lbd(v, X[i].f) - v.begin() + 1;
A[discX[i]] = max(A[discX[i]], X[i].s);
}
int M = v.size();
set <pi> left;
FOR(i,1,M) left.insert(pi(A[i], i));
root = new node(1,M);
int ans = 0;
while (!left.empty()){
pi cur = *left.rbegin();
//~ cerr << cur.f << ' ' << cur.s << '\n';
while (root->qry(1,cur.s,1).f <= cur.f - v[cur.s-1]){
pi x = root->qry(1,cur.s,1);
//~ cerr << x.s << ' ';
assert(left.find(pi(A[x.s], x.s)) != left.end());
left.erase(pi(A[x.s], x.s));
root->upd(x.s);
}
//~ cerr << '\n';
while (root->qry(cur.s+1,M,2).f <= cur.f + v[cur.s-1]){
pi x = root->qry(cur.s+1,M,2);
//~ cerr << x.s << ' ';
assert(left.find(pi(A[x.s], x.s)) != left.end());
left.erase(pi(A[x.s], x.s));
root->upd(x.s);
}
//~ cerr << "\n\n";
ans++;
}
cout << ans;
}
