#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:x) cout << it << " "; cout << #y << endl;
typedef pair<int,int>pii;
typedef pair<pii,pii>pi2;
void solve(){
int n;
cin >> n;
pii arr[n];
for(int x=0;x<n;x++){
cin >> arr[x].first >> arr[x].second;
}
sort(arr,arr+n);
bool done[n];
memset(done,0,sizeof(done));
int counter=0;
while(1){
int maxi=-1;
int index=-1;
for(int x=0;x<n;x++){
if(!done[x]){
if(arr[x].second>maxi){
maxi=arr[x].second;
index=x;
}
}
}
if(maxi==-1) break;
done[index]=true;
for(int x=0;x<index;x++){
if(!done[x]&&arr[index].first-arr[index].second<=arr[x].first-arr[x].second){
done[x]=true;
}
}
for(int x=index+1;x<n;x++){
if(!done[x]&&arr[index].first+arr[index].second>=arr[x].first+arr[x].second) done[x]=true;
}
counter++;
}
cout << counter;
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
//freopen("in.txt", "r", stdin);
int t=1;
//cin >> t;
while(t--){
solve();
}
}
