#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N=5e5+5,mod=1e9+7,inf=1e18;
int n,a[N],x,e,s[N],d[N],mx,ans;
vector <pair<int,int> > v;
bool cmp(pair<int, int> a, pair<int, int> b) {
if (a.first != b.first) {
return a.first < b.first;
}
return a.second>b.second;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n;
for (int i=1; i<=n; i++){
cin>>x>>e;
s[i]=x+e; d[i]=x-e;
v.push_back({d[i],s[i]});
}
sort(v.begin(),v.end(),cmp); mx=-inf;
for (auto i:v){
if (i.second>mx){
ans++; mx=i.second;
}
}
cout<<ans;
}
