#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define pii pair<int, int>
#define ff first
#define ss second
int us[500100];
void solve(){
int n;
cin>>n;
vector<pii> q;
for(int i=1; i<=n; i++){
int l, r;
cin>>l>>r;
q.pb({l, r});
}
sort(q.begin(), q.end());
multiset<pii> d1, d2;
for(int i=0; i<n; i++){
d2.insert({q[i].ff + q[i].ss, i});
}
for(int i=0; i<n; i++){
if(us[i]) continue;
d2.erase(d2.find({q[i].ff + q[i].ss, i}));
int x = q[i].ff - q[i].ss;
while(d1.size() and (*d1.rbegin()).ff >= x){
us[(*d1.rbegin()).ss] = 1;
d1.erase(--(d1.end()));
}
x = q[i].ff + q[i].ss;
while(d2.size() and (*d2.begin()).ff <= x){
us[(*d2.begin()).ss] = 1;
d2.erase(d2.begin());
}
d1.insert({q[i].ff - q[i].ss, i});
}
int ans = 0;
for(int i=0; i<n; i++){
if(us[i] == 0) ans++;
}
cout<<ans;
}
int main(){
solve();
}
