#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pll pair<int, int>
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define endl '\n'
#define ld long double
#define sz(x) static_cast<int>((x).size())
#define i5 tuple<int,int,int,int,int>
#define all(x) x.begin(), x.end()
#define iiii tuple<int, int,int,int>
signed main(){
int n;cin>>n;
vector<pll> v(n);
for(int i=0;i<n;i++)cin>>v[i].f>>v[i].s;
sort(all(v));
vector<pll> in={v[0]};
for(int i=1;i<n;i++){
if(v[i].f - in.back().f <= in.back().s - v[i].s)continue;
while(!in.empty() and v[i].f - in.back().f <= v[i].s - in.back().s)in.pop_back();
in.pb(v[i]);
}
cout<<sz(in);
}
