#include <bits/stdc++.h>
#define ll long long
#define fastio ios::sync_with_stdio(0), cin.tie(0)

using namespace std;

void solve()
{
    int n;
    cin >> n;
    vector<pair<int, int>> v(n);
    for(int i = 0; i < n; i++) {
        cin >> v[i].second >> v[i].first;
    }
    if(n == 1) {
        cout << "1\n";
        return;
    }
    sort(v.begin(), v.end());
    int ans = 0;
    for(int i = 0; i < n; i++) {
        if(i == 0 && v[i].first < v[i + 1].second) {
            ans++;
            continue;
        }
        else if(i == 0) break;
        if(i == n - 1 && v[i].second > v[i - 1].first) {
            ans++;
            continue;
        }
        else if(i == n - 1) break;
        if(v[i].second > v[i - 1].first && v[i].first < v[i + 1].second) ans++;
        else break;

    }
    cout << ans << '\n';
    return;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}