#include <bits/stdc++.h>
using namespace std;
#define int long long
#define INF (int)1e18
#define f first
#define s second
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
void Solve()
{
int n;
cin>>n;
vector <pair<int, int>> v;
int x[n], e[n];
for (int i=0; i<n; i++)
cin>>x[i]>>e[i];
for (int i=0; i<n; i++){
v.push_back({x[i] - e[i] , x[i] + e[i]});
}
sort(v.begin(), v.end());
int best = -INF;
int c = 0;
for (int i=0; i<n; i++){
if (i!=n-1 && v[i].f == v[i+1].f) continue;
int val = v[i].s;
if (val > best){
best = val;
c++;
}
}
cout<<c<<"\n";
}
int32_t main()
{
auto begin = std::chrono::high_resolution_clock::now();
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
for(int i = 1; i <= t; i++)
{
//cout << "Case #" << i << ": ";
Solve();
}
auto end = std::chrono::high_resolution_clock::now();
auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";
return 0;
}
