// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
template<class T> using V = vector<T>;
using vi = V<int>;
using ll = long long;
using pi = pair<int, int>;
using vpi = V<pi>;
using vl = V<ll>;
using db = double;
const int INF = 1e9 + 10;
int main() {
cin.tie(0)->sync_with_stdio(0);
int N; cin >> N;
vi L(N), R(N);
for(int i = 0; i < N; i++) {
int x, y; cin >> x >> y;
L[i] = x - y, R[i] = x + y;
}
vi ord(N); iota(begin(ord), end(ord), 0);
sort(begin(ord), end(ord), [&](int x, int y) {
if (L[x] == L[y]) return R[x] > R[y];
return L[x] < L[y];
});
int r = -INF, ans = 0;
for(auto& i : ord) {
// cout << i << " " << L[i] << " " << R[i] << endl;
if (r < R[i]) ans++, r = R[i];
}
cout << ans << nl;
exit(0-0);
}
