#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<ll> vi;
typedef pair<ll, ll> pi;
#define FOR(i, j, k) for (ll i = j; i < (ll) k; ++i)
#define FORD(i, j, k) for (ll i = j; i >= (ll) k; --i)
#define nl "\n"
#define sp " "
#define all(x) (x).begin(), (x).end()
#define sc second
#define fr first
#define pb emplace_back
struct BIT {
ll n;
vi tree;
BIT(ll N) {
n = N;
tree.resize(n, 0);
}
void add(ll x, ll k) {
while(k <= n) {
tree[k] += x;
k += k&-k;
}
}
ll get(ll k) {
ll sum = 0;
while(k >= 1) {
sum += tree[k];
k -= k&-k;
}
return sum;
}
};
void solve()
{
ll n;
cin >> n;
ll x[n + 1], y[n + 1];
FOR(i, 1, n + 1) {
cin >> x[i] >> y[i];
}
vector<array<ll, 3>> a(n + 1);
for(int i = 1; i <= n; ++i) {
a[i] = {x[i], y[i], i};
}
ll left[n + 1] = {}, right[n + 1] = {};
for(int i = 1; i <= n; ++i) {
for(int j = i; j >= 1; --j) {
if(abs(x[j] - x[i]) <= y[i] - y[j])
left[i] = j;
else
break;
}
for(int j = i; j <= n; ++j) {
if(abs(x[j] - x[i]) <= y[i] - y[j])
right[i] = j;
else
break;
}
}
sort(1 + all(a), [&](array<ll, 3> lhs, array<ll, 3> rhs) {
return lhs[1] > rhs[1];
});
ll ans = 0;
BIT bit(n + 5);
for(int i = 1; i <= n; ++i) {
if(bit.get(a[i][2])) continue;
++ans;
bit.add(1, left[a[i][2]]);
bit.add(-1, right[a[i][2]] + 1);
}
cout << ans << nl;
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
ll t = 1;
// cin >> t;
while (t--)
{
solve();
}
}
