#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl "\n"
#define mod 1000000007
const int N=(1ll<<20);
array <int,2> Tree[2][N*2+5];
int n,E[500001],X[500001],inf=1e17;
map <int,int> key;
set <int> st;
void update(int i,int u,int val,int idx){
i+=N;
Tree[u][i]={val,idx};
i/=2;
while(i!=0){
Tree[u][i]=max(Tree[u][i*2],Tree[u][i*2+1]);
i/=2;
}
return;
}
array <int,2> solve(int l1,int r1,int i,int l,int r,int u){
if(l1>r||l>r1) return {-inf,-1};
if(l<=l1&&r1<=r) return Tree[u][i];
return max(solve(l1,(l1+r1)/2,i*2,l,r,u),solve((l1+r1)/2+1,r1,i*2+1,l,r,u));
}
bool cover(int i,int j){
if(i==-1) return 0;
return ((E[i]-E[j])>=abs(X[i]-X[j]));
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin>>n;
vector <array<int,2>> v;
for(int i=0;i<=N*2+4;i++) Tree[0][i]=Tree[1][i]={-inf,-1};
for(int i=1;i<=n;i++){
cin>>X[i]>>E[i];
st.insert(X[i]);
v.push_back({E[i],i});
}
int comp=1;
for(int i:st) key[i]=comp++;
sort(v.begin(),v.end());
reverse(v.begin(),v.end());
int ans=0;
for(auto [val,i]:v){
int idx1=solve(0,N-1,1,key[X[i]],n,0)[1],idx2=solve(0,N-1,1,1,key[X[i]],1)[1];
if(cover(idx1,i)==1||cover(idx2,i)==1) continue;
ans++;
update(key[X[i]],0,E[i]-X[i],i);
update(key[X[i]],1,E[i]+X[i],i);
}
cout<<ans<<endl;
}
//179276892
