#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pa pair<int, int>
#define tup tuple<int, int, int>
#define db double
#define fi first
#define se second
#define ull unsigned long long
const int maxn = 1e6 + 4, INF = 1e17 + 4, lg = 17, base = 31, mod = 1e9 + 7;
vector <pa> p;
deque <int> dq;
int cnt[maxn];
int n;
void nhap()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n;
for (int i = 1 ; i <= n ; i ++)
{
int x , e;
cin >> x >> e;
p.push_back({x - e , i});
p.push_back({x + e , i});
}
}
bool cmp(pa a , pa b)
{
if (a.fi == b.fi)
return a.se > b.se;
return a.fi < b.fi;
}
void Solve()
{
int ans = 0;
for (auto [pos , i] : p)
{
cnt[i] ++;
if (!dq.empty() && dq.front() == i && cnt[i] == 2)
{
while (!dq.empty() && cnt[dq.front()] == 2)
dq.pop_front();
ans ++;
}
else
dq.push_back(i);
}
cout << ans << '\n';
}
signed main()
{
nhap();
sort(p.begin() , p.end() , cmp);
// for (auto [pos , i] : p)
// cout << pos << ' ' << i << '\n';
Solve();
}
