#include <bits/stdc++.h>
using namespace std;
#define int long long
#define all(x) x.begin(), x.end()
const int inf = 1e18;
signed main(){
ios::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
int n;
cin >> n;
vector<pair<int, int>> v;
for(int i = 1, x, e; i <= n; ++i){
cin >> x >> e;
v.push_back({x - e, x + e});
}
sort(all(v), [&](pair<int, int> x, pair<int, int> y){
if(x.first == y.first) return x.second > y.second;
return x.first < y.first;
});
int mx = v[0].second, ans = 1;
vector<int> dp(n, 0);
dp[0] = 1;
for(int j = 1; j < n; ++j){
if(mx >= v[j].second) dp[j] = 0;
else dp[j] = 1;
mx = max(mx, v[j].second);
ans += dp[j];
}
cout << ans << "\n";
return 0;
}
