#include<bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define ll long long int
const ll N = 100+5 , INF = 1e18 , MOD = 1e9+7;
bool inside(ll x1 , ll y1 , ll x2 , ll y2){
return (abs(x2-x1) <= (y2-y1));
}
void solve(){
ll n;
cin >> n;
vector<pair<ll,ll>> a(n+5);
for(ll i = 1; i <= n; i++) cin >> a[i].first >> a[i].second;
vector<ll> left(n+5) , right(n+5);
for(ll i = 1; i <= n; i++){
for(ll j = i; j >= 1; j--){
if(inside(a[j].first,a[j].second,a[i].first,a[i].second)) left[i] = j;
else break;
}
}
for(ll i = 1; i <= n; i++){
for(ll j = i; j <= n; j++){
if(inside(a[j].first,a[j].second,a[i].first,a[i].second)) right[i] = j;
else break;
}
}
set<pair<ll,ll>> s;
for(ll i = 1; i <= n; i++) s.insert(make_pair(a[i].second,i));
ll ans = 0;
while(s.size()){
auto it = s.end();
it--;
pair<ll,ll> u = (*(it));
ans++;
for(ll i = u.second+1; i <= right[u.second]; i++){
if(s.count(make_pair(a[i].second,i))){
s.erase(s.find(make_pair(a[i].second,i)));
}
}
for(ll i = u.second-1; i >= left[u.second]; i--){
if(s.count(make_pair(a[i].second,i))){
s.erase(s.find(make_pair(a[i].second,i)));
}
}
s.erase(it);
}
cout << ans;
}
int main(){
fast;
ll tc = 1;
// cin >> tc;
while(tc--) solve();
return 0;
}
