#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ll long long
#define ar array
#define ld long double
const int N = 2000, MOD = 1e9 + 7, INF = 1e17;
signed main(){ios::sync_with_stdio(false);cin.tie(0);
int n;
cin>>n;
ar<int, 2> A[n];
for(int i = 0;i<n;i++){
int x, e;
cin>>x>>e;
A[i] = {x - e, x + e};
}
sort(A, A+n, [](auto a,auto b){
return a[0] < b[0] || (a[0] == b[0] && a[1] > b[1]);
});
int ans = 0;
int x = 0;
for(int i = 0;i<n;i++){
if(A[i][1] > x){
ans++;
x = A[i][1];
}
}
cout<<ans;
}
