#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
//#define int long long
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;
signed main() {
int n;
cin >> n;
vector<pii> v(n);
for(int i=0; i<n; i++) {
int a, b;
cin >> a >> b;
v[i] = { a - b, a + b };
}
sort(v.begin(), v.end(), [&](pii a, pii b) {
if(a.first != b.first) return (a.first > b.first);
return a.second < b.second;
});
stack<int> st;
for(int i=0; i<n; i++) {
while(!st.empty() && st.top() <= v[i].second) st.pop();
st.push(v[i].second);
}
cout << st.size() << '\n';
return 0;
}
