#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
#define pb push_back
const int N=5e5+5,MAXN=1e5+5,MAXA=1e6+5,inf=1e18,MOD=998244353;
int seg[N*4][2],offset=1;
void update(int idx,int val,bool type){
idx+=offset;
if(!type)seg[idx][type]=min(seg[idx][type],val);
else seg[idx][type]=max(seg[idx][type],val);
idx/=2;
while(idx>0){
if(!type)seg[idx][type]=min(seg[idx*2][type],seg[idx*2+1][type]);
else seg[idx][type]=max(seg[idx*2][type],seg[idx*2+1][type]);
idx/=2;
}
}
int query(int node,int qlo,int qhi,int lo,int hi,bool type){
if(lo>=qlo && hi<=qhi)return seg[node][type];
if(lo>qhi || hi<qlo)return (type?0LL:inf);
int mid=(lo+hi)/2;
int x=query(node*2,qlo,qhi,lo,mid,type),y=query(node*2+1,qlo,qhi,mid+1,hi,type);
if(!type)return min(x,y);
return max(x,y);
}
signed main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
/*
* xj<=xi -> xi-xj<=ei-ej -> xi-ei<=xj-ej
* xj>xi -> xj-xi<=ei-ej -> xj+ej<=xi+ei
*/
for(int i=0;i<N*4;i++)seg[i][0]=inf;
int n; cin>>n;
pair<int,int> p[n];
set<int> st;
for(int i=0;i<n;i++){
cin>>p[i].second>>p[i].first;
st.insert(p[i].second);
}
map<int,int> id,og;
int cnt=0;
for(auto i:st){
og[cnt]=i;
id[i]=cnt++;
}
while(offset<=cnt)offset*=2;
for(int i=0;i<n;i++)p[i].second=id[p[i].second];
sort(p,p+n);
int ans=0;
for(int i=n-1;i>=0;i--){
int real=og[p[i].second];
if(query(1,p[i].second,offset-1,0,offset-1,0)<=real-p[i].first)continue;
if(real+p[i].first<=query(1,0,p[i].second,0,offset-1,1))continue;
ans++;
update(p[i].second,real-p[i].first,0);
update(p[i].second,real+p[i].first,1);
}
cout<<ans;
}
