#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
const ll N = 1e6 + 5;
const ll inf = LLONG_MAX/4;
const ll mod =  1e9 + 7;
const ll bs = 370;
#define bit(x,y) ((x >> y) & 1)
ll n;
pair<ll,ll> a[N];
pair<ll,ll> b[N];
ll bl[N],l[N],r[N],lzl[N],lzr[N],haha[N];
ll get(ll id)
{
    ll bid = bl[id];
    return max(haha[id],max(lzl[bid] - (a[id].first - a[l[bid]].first),lzr[bid] - (a[r[bid]].first - a[id].first)));
}
int main()
{
    ll i,j;
    cin >> n;
    for(i = 1;i <= n;i++)
    {
        cin >> a[i].first >> a[i].second;
    }
    sort(a + 1,a + 1  + n);
    ll m  = 0;
    for(i = 1;i <= n;i += bs)
    {
        ++m;
        l[m]  = i;
        r[m] = min(n,i + bs - 1);
        lzl[m] = lzr[m] = -inf;
        for(j = l[m];j <= r[m];j++)
        {
            bl[j] = m;
            haha[j] = -inf;
        }
    }
    for(i = 1;i <= n;i++)
    {
        b[i] = {a[i].second,i};
    }
    sort(b + 1,b + 1 + n,greater<pair<ll,ll>>());
    ll ans = 0;
    for(i = 1;i <= n;i++)
    {
        if(get(b[i].second) >= b[i].first) continue;
        ans++;
        ll id = b[i].second;
        ll bid = bl[id];
        haha[id] = max(haha[id],b[i].first);
        for(j = id - 1;j >=  l[bid];j--)
        {
            haha[j] = max(haha[j],b[i].first - (a[id].first - a[j].first));
        }
        for(j = id + 1;j <= r[bid];j++)
        {
            haha[j] = max(haha[j],b[i].first - (a[j].first - a[id].first));
        }
        for(j = bid - 1;j >= 1;j--)
        {
            lzr[j] = max(lzr[j],b[i].first - (a[id].first - a[r[j]].first));
        }
        for(j = bid + 1;j <= m;j++)
        {
            lzl[j] = max(lzl[j],b[i].first - (a[l[j]].first - a[id].first));
        }
    }
    cout << ans;
}