#include <bits/stdc++.h>
using namespace std;
void setup()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
struct SEGMENT_TREE
{
int tree[2000000];
inline SEGMENT_TREE()
{
fill_n(tree, 2000000, -2e9);
}
inline void Update(int ind, int l, int r, int x, int v)
{
if (r < x || x < l)
{
return;
}
if (l == r)
{
tree[ind] = max(tree[ind], v);
return;
}
int m = (l + r) >> 1;
Update(ind << 1, l, m, x, v);
Update(ind << 1 | 1, m + 1, r, x, v);
tree[ind] = max(tree[ind << 1], tree[ind << 1 | 1]);
}
inline int Get(int ind, int l, int r, int x, int y)
{
if (r < x || y < l)
{
return -2e9;
}
if (x <= l && r <= y)
{
return tree[ind];
}
int m = (l + r) >> 1;
return max(Get(ind << 1, l, m, x, y), Get(ind << 1 | 1, m + 1, r, x, y));
}
} st1, st2;
int n, a, b, c[500000], d, m, res;
pair<int, int> p[500000];
int main()
{
setup();
cin >> n;
res = n;
for (int i = 0; i < n; ++i)
{
cin >> p[i].second >> p[i].first;
c[i] = p[i].second;
}
sort(c, c + n);
m = unique(c, c + n) - c;
sort(p, p + n, greater<pair<int, int>>());
for (int i = 0; i < n; ++i)
{
d = lower_bound(c, c + m, p[i].second) - c + 1;
a = st1.Get(1, 1, m, 1, d);
b = st2.Get(1, 1, m, d, m);
if (p[i].first + p[i].second <= a ||
p[i].first - p[i].second <= b)
{
res--;
}
st1.Update(1, 1, m, d, p[i].first + p[i].second);
st2.Update(1, 1, m, d, p[i].first - p[i].second);
}
cout << res;
return 0;
}
