#include <bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
#define fs first
#define sc second
#define ll long long
#define int ll
const ll inf = 1e12;
const ll mxn = 5e5+10;
pii arr[mxn];
int brr[mxn];
bitset<mxn> done;
int N;
struct SEG{
ll seg[mxn*4];
SEG(){
fill(seg,seg+mxn*4,-inf);
}
void modify(int now,int l,int r,int s,int e,int v){
if(l>=s&&e>=r){
seg[now] = max(seg[now],v);
return;
}
int mid = (l+r)>>1;
if(mid>=s)modify(now*2+1,l,mid,s,e,v);
if(mid<e)modify(now*2+2,mid+1,r,s,e,v);
}
int getval(int now,int l,int r,int p){
if(l == r)return seg[now];
int mid = (l+r)>>1;
if(mid>=p)return max(seg[now],getval(now*2+1,l,mid,p));
else return max(seg[now],getval(now*2+2,mid+1,r,p));
}
};
SEG lseg,rseg;
main(){
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>N;
for(int i = 1;i<=N;i++){
cin>>arr[i].fs>>arr[i].sc;
brr[i] = i;
}
sort(arr+1,arr+N+1);
sort(brr+1,brr+N+1,[](int a,int b){return arr[a].sc>arr[b].sc;});
int ans = 0;
for(int i = 1;i<=N;i++){
int now = brr[i];
if(lseg.getval(0,1,N,now)>=arr[now].sc-arr[now].fs||rseg.getval(0,1,N,now)>=arr[now].sc+arr[now].fs)continue;
ans++;
lseg.modify(0,1,N,1,now,arr[now].sc-arr[now].fs);
rseg.modify(0,1,N,now,N,arr[now].sc+arr[now].fs);
}
cout<<ans;
}
