#include<bits/stdc++.h>
using namespace std;
using ll = long long;
vector<int> t;
void upd(int v, int tl, int tr, int pos, int val)
{
if(tl == tr) t[v] += val;
else {
int tm = (tl + tr) / 2;
if(pos <= tm) upd(2 * v, tl, tm, pos, val);
else upd(2 * v + 1, tm + 1, tr, pos, val);
t[v] = t[2 * v] + t[2 * v + 1];
}
}
int get(int v, int tl, int tr, int l, int r)
{
if(l > r) return 0;
if(tl == l && tr == r) return t[v];
else {
int tm = (tl + tr) / 2;
return get(2 * v, tl, tm, l, min(r, tm)) +
get(2 * v + 1, tm + 1, tr, max(l, tm + 1), r);
}
}
void comp(vector<int> &v)
{
map<int, int> mp;
for(int &x : v) mp[x] = 1, cout << x << "\n";
int cnt = 0;
for(auto &[f, s] : mp) s = cnt++;
for(int &x : v) x = mp[x], cout << x << "\n";
}
int main()
{
int n;
cin >> n;
vector<pair<int, int>> v(n);
for(auto &[x, y] : v) cin >> x >> y;
sort(v.begin(), v.end());
vector<int> vec1, vec2;
for(auto &[x, y] : v)
{
vec1.push_back(x - y);
vec2.push_back(x + y);
}
set<int> st;
vector<int> cnt(n, 0);
for(int i = 0; i < n; i++)
{
auto it = st.lower_bound(vec2[i]);
if(it != st.end()) cnt[i] = 1;
st.insert(vec2[i]);
}
st.clear();
for(int i = n - 1; i >= 0; i--)
{
auto it = st.lower_bound(-vec1[i]);
if(it != st.end()) cnt[i] = 1;
st.insert(-vec1[i]);
}
int ans = 0;
for(int i = 0; i < n; i++)
if(cnt[i] == 0) ans++;
cout << ans;
}
