#include<iostream>
#include<cstring>
#include<algorithm>
#include<set>
#define int long long
#define x first
#define y second
using namespace std;
const int N = 1e5,INF = 1e12;
typedef pair<int,int> PII;
void solve()
{
	int n;
	cin>>n;
	vector<PII>regs(n+5);
	for(int i=1;i<=n;i++)	scanf("%lld%lld",&regs[i].x,&regs[i].y);
	sort(regs.begin()+1,regs.begin()+n+1);
	if(n==1)
	{
		cout<<1<<endl;
		return;
	}
	int r = -1,ans=n;
	for(int i=1;i<=n;i++)
	{
		if(regs[i].x<=r)
		{
			ans=i-2;
			break;
		}	
		r=max(r,regs[i].y);
	}
	
	cout<<ans<<endl;
}
signed main()
{
	int T = 1;
	cin>>T;
	while(T--)
	{
		solve();
	}
	return 0;
}