#include <bits/stdc++.h>
using namespace std;
#define int long long
#define INF (int)1e18
#define endl '\n'
const int mod = 1000 * 1000 * 1000 + 7;
const int N = 100005;
#define f first
#define s second
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define rrep(i, a, b) for(int i = (a); i > (b); i--)
#define vi vector<int>
#define pii pair<int, int>
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
void Solve() {
int n; cin>>n;
vector<pair<int,int> > a(n);
for (int i = 0; i < n; ++i) {
cin>>a[i].first>>a[i].second;
}
sort(a.begin(), a.end());
stack<pair<int,int>> st;
for (int i = 0; i < n; ++i) {
if (!st.empty() && a[i].first-st.top().first <= st.top().second - a[i].second) continue;
while (!st.empty() && a[i].first - st.top().first <= a[i].second - st.top().second) st.pop();
st.push(a[i]);
}
cout<<st.size()<<endl;
}
int32_t main() {
auto begin = std::chrono::high_resolution_clock::now();
ios_base::sync_with_stdio(false);
cin.tie(0);
int t = 1;
// cin >> t;
for (int i = 1; i <= t; i++) {
//cout << "Case #" << i << ": ";
Solve();
}
auto end = std::chrono::high_resolution_clock::now();
auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";
return 0;
}
