// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define endl '\n';
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL);
#define py cout << "YES" << endl;
#define pn cout << "NO" << endl;
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define int long long
typedef long long ll;
typedef unsigned long long ull;
const ll inf = 1e18;
const ll mod = 1e9+7;
// #ifndef ONLINE_JUDGE
// #include "algo/Standard_Stuff/debug.cpp"
// #else
// #define debug(...) 42
// #endif
// void judge(){
// srand(time(NULL));
// #ifndef ONLINE_JUDGE
// freopen("1.txt","r",stdin);
// freopen("2.txt","w",stdout);
// #endif
// }
// Look for edge cases!!!
signed main(){
fastio; //judge();
int n; cin >> n;
vector<pair<int, int>>points;
for(int i = 0;i<n;i++){
int a,b; cin >> a >> b;
points.pb({a+b,b-a});
}
sort(all(points),[](auto &i, auto &j){
if(i.first!=j.first){
return i.first > j.first;
}
return i.second > j.second;
});
int ans = 0;
int maxi = -1*inf;
for(auto &[x,y]:points){
if(maxi<y){
ans++; maxi = y;
}
}
cout << ans;
}
