#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pi pair<int, int>
#define vi vector<int>
#define vs vector<string>
#define vb vector<bool>
#define vpi vector<pi>
#define pb push_back
#define all(a) (a).begin(), (a).end()
const int mod = 1e9 + 7;
void solve()
{
int n;
cin >> n;
vpi v(n);
vi ch(n, 0);
for (int i = 0; i < n; i++)
{
cin >> v[i].second >> v[i].first;
}
sort(all(v));
int ans = 0, r = n - 1;
while (r >= 0)
{
if (!ch[r])
{
ans++;
}
ch[r] = 1;
for (int r2 = r - 1; r2 >= 0; r2--)
{
if (v[r].first - v[r2].first >= abs(v[r].second - v[r2].second))
{
ch[r2] = 1;
}
}
r--;
}
cout << ans << '\n';
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
int t = 1;
// cin >> t;
while (t--)
{
solve();
}
return 0;
}
