#include<bits/stdc++.h>
#define lson(x) x<<1
#define rson(x) x<<1|1
#define inf 1000000000000000000
//#define int long long
using namespace std;
const int maxn=1e5+5;
pair<int,int>all[maxn];
void solve()
{
    priority_queue<int,vector<int>,greater<> >q;
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>all[i].first>>all[i].second;
    }
    sort(all+1,all+n+1);
    int tail=1,ans=0;
    for(int i=0;;i++)
    {
        while(!q.empty()&&q.top()<i)
            q.pop();
        if(q.empty()&&tail>n)
            break;
        if(q.empty())
            i=all[tail].first;
        while(tail<=n&&all[tail].first==i)
            q.push(all[tail++].second);
        q.pop();
        ans++;
    }
    cout<<ans<<"\n";
}
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t=1;
    cin>>t;
    while(t--)
    {
        solve();
    }
    return 0;
}