#include <bits/stdc++.h>
#define X first
#define Y second
#define PB push_back
#define x first
#define y second
#define pb push_back
#define all(a) begin(a),end(a)

using namespace std;

typedef long long ll;
typedef vector<int> vi;
using pii=pair<int,int>;

const int N = 5e5 + 500;
const int INF = 0x3f3f3f3f;
const int MOD = 998244353;
const char en='\n';
const ll LLINF=1ll<<60;

int t,n,l[N],r[N];

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin>>t;
	while (t--)
	{
		cin>>n;
		for (int i=0;i<n;++i) cin>>l[i]>>r[i];
		set<pii> sr,sl;
		sr.insert({0,l[0]});
		for (int i=1;i<n;++i) if (r[i]!=r[i-1]) sr.insert({i,r[i-1]});
		sl.insert({0,l[0]});
		for (int i=1;i<n;++i) if (l[i]!=l[i-1]) sl.insert({i,l[i]});
		//sl.insert({n,l[n-1]});
		int odg=sl.size()+sr.size();
		/*for (auto x: sl) cout<<x.x<<' '<<x.y<<en;
		cout<<en;
		for (auto x: sr) cout<<x.x<<' '<<x.y<<en;*/
		for (auto x: sr)
		{
			while (sl.size() && sl.begin()->x<x.x) sl.erase(sl.begin());
			if (sl.size() && sl.begin()->y<=x.y) --odg,sl.erase(sl.begin());
		}
		cout<<odg<<en;
	}
}