#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>
#include <stack>
#include <set>
typedef long long llong;
const int MAXN = 200000 + 10;
const int INF = 1e9;
struct Person
{
int x, e;
friend bool operator > (const Person &a, const Person &b)
{
return a.e > b.e;
}
};
int n;
Person p[MAXN];
std::set <std::pair <int,int>> left, right;
void solve()
{
int ans = 0;
std::sort(p + 1, p + 1 + n, std::greater <Person> ());
for (int i = 1 ; i <= n ; ++i)
{
bool thereIs = false;
auto it = left.lower_bound({p[i].e - p[i].x, 0});
if (it != left.end() && it->second >= p[i].x)
{
thereIs = true;
}
it = right.lower_bound({p[i].x + p[i].e, 0});
if (it != right.end() && it->second <= p[i].x)
{
thereIs = true;
}
if (!thereIs)
{
ans++;
// while (left.size())
// {
// auto it = left.lower_bound({p[i].e - p[i].x, 0});
// if (it != left.end() && it->second <= p[i].x)
// {
// left.erase(it);
// } else
// {
// break;
// }
// }
left.insert({p[i].e - p[i].x, p[i].x});
// while (right.size())
// {
// auto it = right.lower_bound({p[i].x + p[i].x, 0});
// if (it != right.end() && it->second >= p[i].x)
// {
// right.erase(it);
// } else
// {
// break;
// }
// }
right.insert({p[i].x + p[i].e, p[i].x});
}
}
std::cout << ans << '\n';
}
void input()
{
std::cin >> n;
for (int i = 1 ; i <= n ; ++i)
{
std::cin >> p[i].x >> p[i].e;
}
}
void fastIOI()
{
std::ios_base :: sync_with_stdio(0);
std::cout.tie(nullptr);
std::cin.tie(nullptr);
}
int main()
{
fastIOI();
input();
solve();
return 0;
}
