#include <bits/stdc++.h>
#define int long long
#define F first
#define S second
#define pii pair<int,int>
const int mod = 1e9 + 7;
const int mxN = (1 << 22) + 1;
using namespace std;
set<pii>s;
bool cmp(pii a, pii b){
return tie(a.S,a.F) > tie(b.S,b.F);
}
pii a[mxN];
signed main(){
int n;
cin >>n;
for(int i = 1;i <= n;i++) cin >>a[i].F>>a[i].S;
sort(a + 1,a + n + 1,cmp);
for(int i = 1;i <= n;i++){
auto x = s.lower_bound(a[i]);
if(x != s.end()) if(abs(x->F - a[i].F) <= x->S - a[i].S) continue;
if(x != s.begin()){
x--;
if(abs(x->F - a[i].F) <= x->S - a[i].S) continue;
}
s.insert(a[i]);
}
cout<<s.size();
}
