#include <bits/stdc++.h>
using namespace std;
#define int long long
void solve(){
int n; cin >> n;
vector<array<int, 2>> a(n + 1); //0 = x, 1 = e;
for(int i = 1; i <= n; i++) cin >> a[i][0] >> a[i][1];
sort(a.begin() + 1, a.end());
stack<int> s;
vector<int> deg(n + 1), del(n + 1); //xét i < j
for(int i = 1; i < n; i++) del[i] = (a[i] == a[i + 1]);
for(int i = 1; i <= n; i++){ //xi - xj >= ei - ej -> xi - ei >= xj - ej
if(del[i]) continue;
while(s.size() && a[s.top()][0] - a[s.top()][1] >= a[i][0] - a[i][1]){
deg[s.top()]++;
s.pop();
}
s.push(i);
}
while(s.size()) s.pop();
for(int i = n; i >= 1; i--){ //xj - xi >= ei - ej -> xj + ej >= xi + ei
if(del[i]) continue;
while(s.size() && a[s.top()][0] + a[s.top()][1] <= a[i][0] + a[i][1]){
deg[s.top()]++;
s.pop();
}
s.push(i);
}
int ans = 0;
for(int i = 1; i <= n; i++) ans += (deg[i] == 0);
cout << ans;
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
solve();
}
