#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) (x).begin(), (x).end()
template<class T> struct ST {
static constexpr T ID = {(int) -1e9, (int) -1e9}; // or whatever ID
inline T comb(T a, T b) { return {max(a[0], b[0]), max(a[1], b[1])}; } // or whatever function
int sz;
vector<T> t;
void init(int _sz, T val = ID) {
t.assign((sz = _sz) * 2, ID);
}
void init(vector<T> &v) {
t.resize((sz = v.size()) * 2);
for (int i = 0; i < sz; ++i)
t[i + sz] = v[i];
for (int i = sz - 1; i; --i)
t[i] = comb(t[i * 2], t[(i * 2) | 1]);
}
void upd(int i, T x) {
for (t[i += sz] = x; i > 1; i >>= 1)
t[i >> 1] = comb(t[i], t[i ^ 1]);
}
T query(int l, int r) {
T ql = ID, qr = ID;
for (l += sz, r += sz + 1; l < r; l >>= 1, r >>= 1) {
if (l & 1) ql = comb(ql, t[l++]);
if (r & 1) qr = comb(t[--r], qr);
}
return comb(ql, qr);
}
};
int main() {
cin.tie(0)->sync_with_stdio(false);
int n;
cin >> n;
vector<array<int, 2>> a(n);
vector<int> pos;
for (auto &[x, e] : a) {
cin >> x >> e;
pos.push_back(x);
}
sort(all(a), greater<>());
sort(all(pos));
pos.erase(unique(all(pos)), pos.end());
vector<array<int, 2>> b;
for (auto &[x, e] : a)
if (b.empty() || x != b.back()[0])
b.push_back({x, e});
sort(all(b), [&](array<int, 2> &x, array<int, 2> &y) { return x[1] > y[1]; });
ST<array<int, 2>> st;
st.init(n + 1);
int ans = b.size();
for (auto &[x, e] : b) {
int i = lower_bound(all(pos), x) - pos.begin();
if (st.query(i, n)[0] >= e - x || st.query(0, i)[1] >= e + x)
ans--;
st.upd(i, {e - x, e + x});
}
cout << ans << '\n';
return 0;
}
