#include <iostream>
#include <chrono>
#include <vector>
#include <algorithm>
#define maxn 500005
#define maxlog 20
#define INF 1000000010
#define LINF 1000000000000000005
#define endl '\n'
#define pb(x) push_back(x)
#define X first
#define Y second
#define control cout<<"passed"<<endl;
#pragma GCC optimize("O3" , "Ofast" , "unroll-loops" , "fast-math")
#pragma GCC target("avx2")
using namespace std;
std::chrono::high_resolution_clock::time_point startT, currT;
constexpr double TIME_MULT = 1;
double timePassed()
{
using namespace std::chrono;
currT = high_resolution_clock::now();
double time = duration_cast<duration<double>>(currT - startT).count();
return time * TIME_MULT;
}
int n;
int a[maxn];
int p[maxn];
vector <pair <int , int >> res;
bool cmp(pair <int , int> e1 , pair <int , int> e2)
{
return e1.X != e2.X? e1.X < e2.X : e1.Y > e2.Y;
}
void read()
{
cin >> n;
res.resize(n);
for(int i = 0; i < n; i++)
cin >> a[i] >> p[i];
for(int i = 0; i < n; i++)
{
res[i].X = a[i] - p[i];
res[i].Y = a[i] + p[i];
}
sort(res.begin() , res.end() , cmp);
int maxx = -1 , br = 0;
for(pair <int , int> e : res)
if(e.Y > maxx)
{
maxx = e.Y;
br++;
}
cout << br << endl;
}
int main()
{
/**#ifdef ONLINE_JUDGE
freopen("taxi.in", "r", stdin);
freopen("taxi.out", "w", stdout);
#endif*/
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
startT = std::chrono::high_resolution_clock::now();
read();
return 0;
}
