#include<bits/stdc++.h>
#define newl '\n'
const int N = 5e5 + 10;
const int V = 1e7 + 10;
const long long INF = 1e18;
const long long M = 1e9 + 7;
struct SegmentTree{
std::vector<int> st;
SegmentTree(int n) : st(n * 4 + 10,0){
}
void update(int l,int r,int pos,int val,int id = 1){
if(l == r){
st[id] = val;
return;
}
int mid = (l + r) / 2;
if(pos <= mid){
update(l,mid,pos,val,id << 1);
}else{
update(mid + 1,r,pos,val,id << 1 | 1);
}
st[id] = std::max(st[id << 1],st[id << 1 | 1]) ;
}
int query(int l,int r,int u,int v,int id = 1){
if(u <= l && r <= v){
return st[id];
}
int mid = (l + r) / 2;
if(v <= mid){
return query(l,mid,u,v,id << 1);
}
if(u > mid){
return query(mid + 1,r,u,v,id << 1 | 1);
}
return std::max(query(l,mid,u,v,id << 1),query(mid + 1,r,u,v,id << 1 | 1));
}
};
int n,id[N + 1];
std::pair<int,int> p[N + 1];
std::vector<int> c;
void readData(){
std::cin >> n;
for(int i = 1;i <= n;++i){
int x,e;
std::cin >> x >> e;
p[i] = {x - e,x + e};
c.emplace_back(p[i].first);
}
auto cmp = [&](std::pair<int,int> &lhs,std::pair<int,int> &rhs){
return (lhs.first < rhs.first || (lhs.first == rhs.first && lhs.second < rhs.second));
};
std::sort(p + 1,p + n + 1,cmp);
std::sort(c.begin(),c.end());
c.erase(std::unique(c.begin(),c.end()),c.end());
}
int get_id(int val){
return std::lower_bound(c.begin(),c.end(),val) - c.begin() + 1;
}
void solve(){
SegmentTree st(n);
int ans = 0;
for(int i = 1;i <= n;++i){
int id = get_id(p[i].first);
if(st.query(1,n,1,id) < p[i].second){
++ans;
}
st.update(1,n,id,p[i].second);
}
std::cout << ans;
}
int main(){
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);std::cout.tie(nullptr);
readData();
solve();
return 0;
}
