#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define fst first
#define snd second
#define pb push_back
#define forn(i,a,b) for(int i = a; i < b; i++)
#define ALL(x) x.begin(),x.end()
#define SZ(x) (int)x.size()
#define mset(a,v) memset((a),(v),sizeof(a))
#define FIN ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define dbg(v) cout<<"Line("<<__LINE__<<"): "<<#v<<" = "<<v<<'\n';
#define pi pair<int,int>
#define pll pair<ll,ll>
typedef long long ll;
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;
typedef tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update> indexed_multiset;
int main(){FIN;
ll n; cin>>n;
vector< pair<ll,ll> > person(n);
set< pair<ll,ll> > priority;
forn(i,0,n) cin>>person[i].fst>>person[i].snd, priority.insert({person[i].snd,person[i].fst});
sort(ALL(person));
ll res = 0;
while(!priority.empty()){
auto it = --priority.end();
auto newIt = priority.begin();
while(newIt!=priority.end()){
auto nnewIt = newIt;
nnewIt++;
if(it!=newIt){
if(abs((*it).snd-(*newIt).snd)<=(*it).fst-(*newIt).fst){
priority.erase(newIt);
}
}
newIt = nnewIt;
}
priority.erase(it);
//cout<<SZ(priority)<<'\n';
res++;
}
cout<<res<<'\n';
return 0;
}
