#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
#define ff first
#define ss second
#define MP make_pair
const int LOG = 22;
const int mxn = 1e6 + 3;
const int mod = 1e9 + 7;
int x[mxn], e[mxn], n;
int d[mxn], s[mxn];
void solve() {
cin >> n;
vector<int> id;
for(int i = 1; i <= n; i++) {
cin >> x[i] >> e[i];
d[i] = e[i] - x[i];
s[i] = e[i] + x[i];
id.push_back(i);
}
sort(id.begin(), id.end(), [&](int i, int j) {
if(d[i] != d[j]) return d[i] > d[j];
return s[i] > s[j];
});
int en = 0, ans = 0;
for(int i : id) {
if(s[i] > en) {
ans++;
en = s[i];
}
}
cout << ans << endl;
}
signed main() {
#ifdef LOCAL
auto start = chrono::high_resolution_clock::now();
#endif
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
signed t = 1; // cin >> t;
while(t--) solve();
#ifdef LOCAL
auto end = chrono::high_resolution_clock::now();
cout << "\n"; for(int i = 0; i <= 20; ++i) cout << '-';
cout << "\nExecution time: " << chrono::duration_cast<chrono::milliseconds> (end - start).count() << "[ms]" << endl;
#endif
return 0;
}
