#include<bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define in insert
#define er erase
#define pb push_back
#define ppb pop_back()
#define ph push
#define pp pop()
#define d3 ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define cans cout << ans << "\n";
#define yes cout << "YES" << "\n";
#define no cout << "NO" << "\n";
#define pll pair<ll,ll>
#define lin cout << "\n";
#define sqr 340
#define mod 1000000007
using namespace std;
pll a[1009];
vector<ll> adj[1009];
bool vis[1009];
void dfs(ll n)
{
if(vis[n])
return;
vis[n]=1;
for(auto it : adj[n])
dfs(it);
}
int main()
{
d3
ll n;
cin >> n;
for(int i = 0 ; n>i ; 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(a[i].F-a[j].F>=abs(a[i].S-a[j].S))
adj[i].pb(j);
ll ans = 0;
for(int i = n-1 ; i>=0 ; i--)
{
if(vis[i])
continue;
ans++;
dfs(i);
}
cans
}
