#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
using namespace __gnu_pbds;
using namespace std;
#define pb push_back
#define st first
#define nd second
typedef long long ll;
typedef long double ld;
const ll I = 1000'000'000'000'000'000LL;
const int II = 2'000'000'000;
const ll M = 1000'000'007LL;
const int N = 1000'007;
pair<int, int> tab[N];
void Solve()
{
int n;
cin >> n;
for(int i = 1; i <= n; ++i)
{
cin >> tab[i].st >> tab[i].nd;
tab[i] = pair{tab[i].st - tab[i].nd, -(tab[i].st + tab[i].nd)};
}
sort(tab + 1, tab + 1 + n);
int cur = -II, ans = 0;
for(int i = 1; i <= n; ++i)
{
tab[i].nd *= -1;
if(tab[i].nd > cur)
{++ans; cur = tab[i].nd;}
}
cout << ans << '\n';
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//int t; cin >> t;
//while(t--)
Solve();
return 0;
}
