#include <bits/stdc++.h>  
using namespace std;  

#define int long long  

void solve() {
	int n;
	cin >> n;

	map<int, vector<pair<int, int>>> xr, yr;
	for (int i = 1; i <= n; i++) {
		int x, y;
		cin >> x >> y;
		xr[x].push_back({y, 0});
		yr[y].push_back({x, 0});
	}

	int m;
	cin >> m;

	for (int i = 1; i <= m; i++) {
		int x, y;
		cin >> x >> y;
		xr[x].push_back({y, 1});
		yr[y].push_back({x, 1});
	}

	using Point = pair<int, int>;

	vector<pair<Point, Point>> ls;
	for (auto &[x, v] : xr) {
		sort(v.begin(), v.end());
		for (int i = 1; i < v.size(); i++) {
			if (v[i].second == 0 && v[i - 1].second == 0) {
				int l = v[i - 1].first + 1, r = v[i].first - 1;
				if (l > r) {
					cout << -1 << "\n";
					return;
				}
				ls.push_back({{x, l}, {x, r}});
			}
		}
	}
	for (auto &[y, v] : yr) {
		sort(v.begin(), v.end());
		for (int i = 1; i < v.size(); i++) {
			if (v[i].second == 0 && v[i - 1].second == 0) {
				int l = v[i - 1].first + 1, r = v[i].first - 1;
				if (l > r) {
					cout << -1 << "\n";
					return;
				}
				ls.push_back({{l, y}, {r, y}});
			}
		}
	}
	// for (auto [a, b] : ls) {
	// 	cout << "(" << a.first << ", " << a.second << ") " << "(" << b.first << ", " << b.second << ") \n";
	// }
	auto ins = [&](pair<Point, Point> a, pair<Point, Point> b) {
		int x = a.first.first, y1 = a.first.second, y2 = a.second.second;
		int y = b.first.second, x1 = b.first.first, x2 = b.second.first;
		if (x == a.second.first && y != b.second.second) {
			return false;
		}
		if (y < y1 || y > y2) {
			return false;
		}
		if (x < x1 || x > x2) {
			return false;
		}
		return true;
	};
	vector<vector<int>> g(ls.size(), vector<int>(ls.size()));
	vector<int> f(ls.size());
	int ans = 0;
	for (int i = 0; i < ls.size(); i++) {
		for (int j = i + 1; j < ls.size(); j++) {
			if (ins(ls[i], ls[j])) {
				g[i][j] = g[j][i] = 1;
				ans++;
				f[i]++, f[j]++;
			}
		}
	} 
	vector<Point> a;
	for (int i = 0; i < ls.size(); i++) {
		if (f[i] == 0) {
			ans++;
			a.push_back(ls[i].first);
		}
		if (f[i] == 1) {
			for (int j = i + 1; j < ls.size(); j++) {
				if (g[i][j]) {
					a.push_back({ls[i].first.first, ls[j].first.second});
				}
			}
			continue;
		}
		for (int j = i + 1; j < ls.size(); j++) {
			if (!g[i][j]) {
				continue;
			}
			if (f[j] >= 2) {
				g[i][j] = g[j][i] = 0;
				f[i]--, f[j]--;
				ans--;
			}
			if (f[i] < 2) {
				continue;
			}
		}
		for (int j = i + 1; j < ls.size(); j++) {
			if (g[i][j]) {
				a.push_back({ls[i].first.first, ls[j].first.second});
			}
		}
	}

	cout << ans << "\n";
	for (auto [x, y] : a) {
		cout << x << " " << y << "\n";
	}
}

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

    int t;
    cin >> t;
    while (t--) {
    	solve();
    }

    return 0;
}