#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2*1e5+5, INF = 4e18+9;
struct people{
ll x, e, id;
};
struct segment{
ll l, r;
};
struct normalize{
vector<ll> poi, pot;
void add(ll x){
poi.push_back(x);
}
void start(){
sort(poi.begin(), poi.end());
if(poi.size() > 0) pot.push_back(poi[0]);
for(int i = 1; i < (int)poi.size(); i++){
if(poi[i] != poi[i-1]){
pot.push_back(poi[i]);
}
}
}
int encode(ll x){
return lower_bound(pot.begin(), pot.end(), x) - pot.begin()+1;
}
};
template <class T>
struct Fenwick {
int n, log;
vector<T> bit;
Fenwick(int n) : n(n), log(32 - __builtin_clz(n + 1)), bit(n + 1, 0) {}
void add(int i, T delta) {
for (; i <= n; i += i & -i) {
bit[i] += delta;
}
}
T sum(int i) {
T res = 0;
for (; i > 0; i -= i & -i) {
res += bit[i];
}
return res;
}
T sum(int l, int r) {
return sum(r)-sum(l-1);
}
int kth(T k) {
T sum = 0;
int pos = 0;
for (int l = log - 1; l >= 0; l--) {
if (pos + (1 << l) <= n && sum + bit[pos + (1 << l)] <= k) {
pos += 1 << l;
sum += bit[pos];
}
}
return pos;
}
};
void solve(){
int n;
cin >> n;
vector<people> a(n+1);
for(int i = 1; i <= n; i++){
cin >> a[i].x >> a[i].e;
a[i].id = i;
}
sort(a.begin()+1, a.end(), [&](people a, people b){return a.e < b.e || (a.e == b.e && a.x < b.x);});
vector<segment> s(1);
normalize norm;
for(int i = 1; i <= n; i++){
s.push_back({a[i].x-a[i].e, a[i].x+a[i].e});
norm.add(s[i].l);
norm.add(s[i].r);
}
norm.start();
for(int i = 1; i <= n; i++){
s[i] = {norm.encode(s[i].l), norm.encode(s[i].r)};
}
int N = norm.pot.size();
Fenwick<int> bit(N+1);
sort(s.begin()+1, s.end(), [&](segment a, segment b){return a.l < b.l || (a.l == b.l && a.r > b.r);});
int ans = 0;
for(int i = 1; i <= n; i++){
if(!bit.sum(s[i].r, N)){
ans++;
}
bit.add(s[i].r, 1);
}
cout << ans;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
solve();
}
