#include<bits/stdc++.h>
#define taskname "B"
using namespace std;
template<class T>void maximize(T& a, T b){
if(a < b){
a = b;
}
}
const int lim = 5e5 + 5;
int n, X[lim], E[lim];
namespace sub1{
void solve(){
map<int, bool>cnt;
for(int i = 1; i <= n; i++){
cnt[X[i]] = true;
}
cout << cnt.size();
}
}
namespace sub23{
void solve(){
map<int, int>repu;
for(int i = 1; i <= n; i++){
maximize(repu[X[i]], E[i]);
}
n = repu.size();
vector<pair<int, int>>vertex;
for(pair<const int, int>& it : repu){
vertex.emplace_back(it);
}
vector<bool>d(n, true);
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
if(i != j && abs(vertex[i].first - vertex[j].first) <= vertex[i].second - vertex[j].second){
d[j] = false;
}
}
}
cout << count(d.begin(), d.end(), true);
}
}
//x[i] - x[j] <= e[i] - e[j] -> x[i] - e[i] <= x[j] - e[j]
//x[j] - x[i] <= e[i] - e[j] -> x[i] + e[i] >= x[j] + e[j]
namespace sub4{
void solve(){
map<int, int>repu;
for(int i = 1; i <= n; i++){
maximize(repu[X[i]], E[i]);
}
n = repu.size();
vector<pair<int, int>>vertex;
for(pair<const int, int>& it : repu){
vertex.emplace_back(it);
}
vector<bool>d(n, true);
priority_queue<pair<int, int>>left;
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>>right;
for(int i = 1; i <= n; i++){
right.emplace(vertex[i].first + vertex[i].second, i);
}
for(int i = 1; i <= n; i++){
int side = vertex[i].first - vertex[i].second;
while(!left.empty()){
auto [S, I] = left.top();
if(S < side){
break;
}
d[I] = false;
left.pop();
}
left.emplace(side, i);
side = vertex[i].first + vertex[i].second;
while(!right.empty()){
auto [S, I] = right.top();
if(S > side){
break;
}
right.pop();
if(I <= i){
continue;
}
d[I] = false;
}
}
cout << count(d.begin(), d.end(), true);
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if(fopen(taskname".inp", "r")){
freopen(taskname".inp", "r", stdin);
}
cin >> n;
for(int i = 1; i <= n; i++){
cin >> X[i] >> E[i];
}
if(*min_element(E + 1, E + n + 1) == *max_element(E + 1, E + n + 1)){
sub1::solve();
}
else if(n <= 1000){
sub23::solve();
}
else{
sub4::solve();
}
}
