#include<bits/stdc++.h>
#define IOS ios_base::sync_with_stdio(false);cin.tie();cout.tie();
#define all(x) x.begin(), x.end()
#define int long long
#define pq priority_queue
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define pb push_back
#define pp pop_back
#define F first
#define S second
using namespace std;
pair<int, int> a[1010];
vector<int> adj[1010];
bool vis[1010];
void dfs(int s) {
if (vis[s]) return ;
vis[s] = 1;
for (auto i: adj[s]) dfs(i);
}
void solve () {
int n;
cin >> n;
for(int i = 0; i < n; i++) cin >> a[i].S >> a[i].F;
sort(a, a + n);
for (int i = n - 1 ; i >= 0 ; i--)
for (int j = i - 1 ; j >= 0; j--)
if (abs(a[i].S - a[j].S) <= a[i].F - a[j].F) adj[i].pb(j);
int ans = 0;
for (int i = n - 1; i >= 0; i--) {
if (vis[i]) continue ;
ans++;
dfs(i);
}
cout << ans;
}
signed main() {IOS solve(); return 0;}
