#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define MAXN (1000005)
int main() {
ios_base::sync_with_stdio(false);cin.tie(0);
ll N;
cin>>N;
pair<ll,ll> arr[N];
for(ll i = 0;i < N;i++){
cin>>arr[i].first>>arr[i].second;
}
sort(arr,arr + N);
if(N > 1000){
set<ll> s;
for(ll i = 0;i < N;i++){
s.insert(arr[i].first);
}
cout<<s.size()<<'\n';
return 0;
}
vector<ll> covered[N];
vector<pair<ll,ll> > v;
for(ll i = 0;i < N;i++){
for(auto u : v){
if(arr[i].first - arr[i].second <= u.first){
covered[i].push_back(u.second);
}
}
v.push_back({arr[i].first - arr[i].second,i});
}
/*for(ll i = 0;i < N;i++){
cout<<"COVERED: ";
for(auto u : covered[i]){
cout<<u<<" ";
}
cout<<'\n';
}*/
bool done[N];
memset(done,0,sizeof(done));
ll ans = 0;
for(ll i = N - 1;i >= 0;i--){
if(!done[i]){
ans++;
done[i] = 1;
for(auto u : covered[i]){
done[u] = 1;
}
}
}
cout<<ans<<'\n';
}
