#include <bits/stdc++.h>
using namespace std;
using ll=long long;
#define sz(a) (int)a.size()
#define f first
#define s second
#define mk make_pair
#define pii pair<int,int>
/*
|Xi - Xj| <= Ei-Ej
TH1:
Xi - Xj <= Ei - Ej
Xi - Ei <= Xj - Ej
TH2:
Xj - Xi <= Ei - Ej
Xj + Ej <= Xi + Ei
*/
bool cmp(pii a,pii b){
if(a.f==b.f) return a.s>b.s;
return a.f<b.f;
}
const int N=5e5+5;
pii M[N];
void solve(){
int n;cin>>n;
for(int i=1;i<=n;++i) {
int a,b;cin>>a>>b;
M[i].f=a-b;
M[i].s=a+b;
}
sort(M+1,M+n+1,cmp);
int ans=0;
int cur=0;
for(int i=1;i<=n;++i){
if(M[i].s>cur){
++ans;
cur=M[i].s;
}
}
cout<<ans;
}
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);
solve();
}
