#include <bits/stdc++.h>
#define int long long
#define ll long long
#define pb push_back
#define fi first
#define se second
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
#define ld long double
using namespace std;
typedef pair<int,int> pii;
typedef pair<char,char> pcc;
typedef pair<int,pii> ipii;
typedef pair<pii,pii> ipiii;
const int MAXN = 5e5+30;
const int SQRT = 610;
const int MAXA = 5e5+10;
const int MOD = 1e6+7;
const int INF = 2e9+10;
const int LOG = 19;
const ld EPS = 1e-12;
void chmx(int &a, int b){ a = max(a,b); }
void chmn(int &a, int b){ a = min(a,b); }
int n, le[MAXN], ri[MAXN], a[MAXN];
pii x[MAXN]; // influence le ri
int ANS;
vector <pii> vec;
bool cmp(pii a, pii b){
if(a.fi==b.fi) return a.se > b.se;
return a.fi < b.fi;
}
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> n;
for(int i=1; i<=n; i++){
int p, q; cin>>p>>q;
x[i].fi = p-q, x[i].se = p+q;
}
sort(x+1, x+n+1, cmp);
int big = -1;
for(int i=1; i<=n; i++){
if(big < x[i].se){
big = x[i].se; ANS++;
}
}
cout << ANS << '\n';
}
