#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>> xl;
	vector<pair<Point, Point>> yl;
	
	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;
				}
				xl.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;
				}
				yl.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 (y < y1 || y > y2) {
			return false;
		}
		if (x < x1 || x > x2) {
			return false;
		}
		return true;
	};

	n = xl.size(), m = yl.size();
	vector<vector<int>> adj(n + m);
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			if (ins(xl[i], yl[j])) {
				adj[i].push_back(j + n);
				adj[j + n].push_back(i);
			}
		}
	}

	vector<int> p(n + m, -1);
	vector<int> vis(n + m);
	function<int(int)> dfs = [&](int x) {
		for (auto y : adj[x]) {
			if (vis[y]) {
				continue;
			}
			vis[y] = true;
			if (p[y] == -1 || dfs(p[y])) {
				p[x] = y;
				p[y] = x;
				return 1;
			}
		}
		return 0;
	};

	int sum = 0;
	for (int i = 0; i < n; i++) {
		vis.assign(n + m, false);
		sum += dfs(i);
	}

	vector<pair<int, int>> ans;
	for (int x = 0; x < n; x++) {
		if (p[x] == -1) {	
			sum++;
			ans.push_back(xl[x].first);
		} else {
			ans.push_back({xl[x].first.first, yl[p[x] - n].first.second});
		}
	}
	for (int x = 0; x < m; x++) {
		if (p[x + n] == -1) {	
			sum++;
			ans.push_back(yl[x].first);
		} 
	}
	

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

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

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

    return 0;
}