#include <bits/stdc++.h>
using namespace std;
#define oo 1e15
#define fi first
#define se second
#define sp(iiii) setprecision(iiii)
#define IO ios_base::sync_with_stdio(false); cin.tie(0)
#define ms(aaaa,xxxx) memset(aaaa,xxxx,sizeof(aaaa))
#define cntbit(xxxx) __builtin_popcount(xxxx)
#define getbit(xxxx,aaaa) ((xxxx>>(aaaa-1))&1)
typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<pair<int,int>,int> piii;
typedef pair<long long,long long> pll;
typedef pair<pair<long long,long long>,long long> plll;
typedef pair<pair<long long,long long>,pair<long long,long long>> pllll;
typedef pair<pair<long long,long long>,bool> pllb;
const ll base=361;
const ll mod=998244353;
const ld eps=1e-5;
const ll maxn=1e9+9;
int n,i,last,res;
pii b[10000009],a[10000009];
int main(){
IO;
cin>>n;
for (i=1;i<=n;i++) {
cin>>a[i].fi>>a[i].se;
b[i]={a[i].fi+a[i].se,a[i].fi-a[i].se};
}
sort(b+1,b+n+1);
last=2e9+7;
for (i=n;i>=1;i--) {
if (b[i].se<last) {
res++;
last=b[i].se;
}
}
cout<<res<<'\n';
}
