#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MOD 998244353
void solve()
{
ll n, x, y, mn = 0, ans = 0;
cin >> n;
vector<pair<ll, ll>> a(n);
for (int i = 0; i < n; i++)
{
cin >> x >> y;
a[i] = {x - y, -x - y};
}
sort(a.begin(), a.end());
for (int i = 0; i < n; i++)
{
if (a[i].second < mn)
{
mn = a[i].second;
ans++;
}
}
cout << ans << '\n';
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int tests = 1;
// cin >> tests;
for (int i = 1; i <= tests; i++)
{
// cout << "Case #" << i << ": ";
solve();
}
return 0;
}
