//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
//#pragma GCC optimize("Ofast,fast-math")
//#pragma GCC target("avx,avx2")
//#pragma GCC optimize(2)
//#pragma GCC optimize(3)
//#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef double db;
#define F(i, a, b) for(int i = a; i <= (b); ++i)
#define F2(i, a, b) for(int i = a; i < (b); ++i)
#define dF(i, a, b) for(int i = a; i >= (b); --i)
template<typename T> void debug(string s, T x) {
	cerr << "[" << s << "] = [" << x << "]\n";
}
template<typename T, typename... Args> void debug(string s, T x, Args... args) {
	for (int i = 0, b = 0; i < (int)s.size(); i++) if (s[i] == '(' || s[i] == '{') b++;
		else if (s[i] == ')' || s[i] == '}') b--;
		else if (s[i] == ',' && b == 0) {
			cerr << "[" << s.substr(0, i) << "] = [" << x << "] | ";
			debug(s.substr(s.find_first_not_of(' ', i + 1)), args...);
			break;
		}
}
#ifdef ONLINE_JUDGE
	#define Debug(...)
#else
	#define Debug(...) debug(#__VA_ARGS__, __VA_ARGS__)
#endif
#define pb push_back
#define fi first
#define se second
#define Mry fprintf(stderr, "%.3lf MB\n", (&Med - &Mbe) / 1048576.0)
#define Try cerr << 1e3 * clock() / CLOCKS_PER_SEC << " ms\n";
typedef long long ll;
// namespace Fread {const int SIZE = 1 << 17; char buf[SIZE], *S, *T; inline char getchar() {if (S == T) {T = (S = buf) + fread(buf, 1, SIZE, stdin); if (S == T) return '\n';} return *S++;}}
// namespace Fwrite {const int SIZE = 1 << 17; char buf[SIZE], *S = buf, *T = buf + SIZE; inline void flush() {fwrite(buf, 1, S - buf, stdout), S = buf;} inline void putchar(char c) {*S++ = c;if (S == T) flush();} struct NTR {~NTR() {flush();}} ztr;}
// #ifdef ONLINE_JUDGE
// #define getchar Fread::getchar
// #define putchar Fwrite::putchar
// #endif
inline int ri() {
	int x = 0;
	bool t = 0;
	char c = getchar();
	while (c < '0' || c > '9') t |= c == '-', c = getchar();
	while (c >= '0' && c <= '9') x = (x << 3) + (x << 1) + (c ^ 48), c = getchar();
	return t ? -x : x;
}
inline void wi(int x) {
	if (x < 0) {
		putchar('-'), x = -x;
	}
	if (x > 9) wi(x / 10);
	putchar(x % 10 + 48);
}
inline void wi(int x, char s) {
	wi(x), putchar(s);
}
bool Mbe;
// mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
const int mod = 998244353;
const int inf = 0x3f3f3f3f;
const ll infll = 0x3f3f3f3f3f3f3f3f;
const int _ = 2e5 + 5;

int n, m;

template<class tp>
struct Flow {
	int Node;
	int s, t, lv[_], cur[_];
	int tot = 1, head[_], to[_ << 1], nxt[_ << 1];
	tp w[_ << 1];
	inline void add(int u, int v, tp dis) {
		to[++tot] = v;
		nxt[tot] = head[u];
		w[tot] = dis;
		head[u] = tot;
	}
	inline void Add(int u, int v, tp dis) {
		add(u, v, dis);
		add(v, u, 0);
	}
	inline bool bfs() {
		F(i, 0, Node) lv[i] = -1;
		lv[s] = 0;
		memcpy(cur, head, sizeof(head));
		queue<int> q;
		q.push(s);
		while (!q.empty()) {
			int p = q.front();
			q.pop();
			for (int eg = head[p]; eg; eg = nxt[eg]) {
				int v = to[eg];
				tp vol = w[eg];
				if (vol > 0 && lv[v] == -1)
					lv[v] = lv[p] + 1, q.push(v);
			}
		}
		return lv[t] != -1;
	}
	tp dfs(int p, tp flow = 2e9) {
		if (p == t)
			return flow;
		tp rmn = flow;
		for (int eg = cur[p]; eg && rmn; eg = nxt[eg]) {
			cur[p] = eg;
			int v = to[eg];
			tp vol = w[eg];
			if (vol > 0 && lv[v] == lv[p] + 1) {
				tp c = dfs(v, min(vol, rmn));
				rmn -= c;
				w[eg] -= c;
				w[eg ^ 1] += c;
			}
		}
		return flow - rmn;
	}
	inline tp dinic() {
		tp ans = 0;
		while (bfs())
			ans += dfs(s);
		return ans;
	}
	void init() {
		F(i, 0, Node) head[i] = 0;
		tot = 1;
		Node = 0;
	}
};
Flow<int> A;

pii a[_], b[_]; int t, C[_];

int mp[805][805], mp1[805][805], mp2[805][805];

bool Med;
signed main() {
	// Mry;
	int T = ri();
	while(T--) {
		A.init();
		n = ri();
		t = 0;
		F(i, 1, n) {
			a[i].fi = ri(), a[i].se = ri();
			C[++t] = a[i].fi, C[++t] = a[i].se;
		}
		m = ri();
		F(i,1 , m) {
			b[i].fi = ri(), b[i].se = ri();
			C[++t] = b[i].fi, C[++t] = b[i].se;
		}
		sort(C + 1, C + t + 1);
		t = unique(C + 1, C + t + 1) - C - 1;
		F(i, 1, n) {
			a[i].fi = lower_bound(C + 1, C + t + 1, a[i].fi) - C;
			a[i].se = lower_bound(C + 1, C + t + 1, a[i].se) - C;
		}
		F(i, 1, m) {
			b[i].fi = lower_bound(C + 1, C + t + 1, b[i].fi) - C;
			b[i].se = lower_bound(C + 1, C + t + 1, b[i].se) - C;
		}
//		t = 10;
		F(i, 1, t) F(j, 1, t) {
			mp[i][j] = mp1[i][j] = mp2[i][j] = 0;
		}
		F(i, 1, n) {
			mp[a[i].fi][a[i].se] = 1;
		}
		F(i, 1, m) {
			mp[b[i].fi][b[i].se] = 2;
		}
//		Debug("haha");
		bool flg = 0;
		int sum = 0;
		int hangnode = 0, lienode = t + t + t;
		static pii Zb[_];
		F(i, 1, t) {
			F(j, 1, t) if(mp[i][j] == 1) {
				int nw = j + 1;
				while(nw <= t && mp[i][nw] != 1) nw++;//, Debug(nw);
//				Debug(i, j);
				if(j < t && j + 1 == nw) {
					flg = 1;
					break;
				}
//				Debug(i, j, nw);
				if(nw == t + 1) break;
				bool fg = 1;
				F(z, j + 1, nw - 1) {
					fg &= (mp[i][z] == 0);
				}
				if(fg) {
					++hangnode;
					sum++;
//					Debug("hang", i, j + 1, nw - 1);
					F(z, j + 1, nw - 1) if(mp[i][z] == 0) mp1[i][z] = hangnode, Zb[hangnode] = {i, z};
				}
//				Debug(t, nw - 1, "done");
				j = nw - 1;
			}
//			Debug(i);
			if(flg) break;
		}
		if(flg) {
			puts("-1");
			continue;
		}
//		Debug("zj");
		F(j, 1, t) {
			F(i, 1, t) if(mp[i][j] == 1) {
				int nw = i + 1;
				while(nw <= t && mp[nw][j] != 1) nw++;
				if(nw == t + 1) break;
				if(i < t && i + 1 == nw) {
					flg = 1;
					break;
				}
				bool fg = 1;
				F(z, i + 1, nw - 1) fg &= (mp[z][j] == 0);
				if(fg) {
					++lienode;
					sum++;
//					Debug("lie", i + 1, nw - 1, j);
					F(z, i + 1, nw - 1) if(mp[z][j] == 0) mp2[z][j] = lienode, Zb[lienode] = {z, j};
				}
				i = nw - 1;
			}
			if(flg) break;
		}
		if(flg) {
			puts("-1");
			continue;
		}
//		Debug("114514");
		A.s = 0, A.t = lienode + 1;
		A.Node = A.t + 2;
		F(i, 1, hangnode) A.Add(A.s, i, 1);
		F(i, t + t + t + 1, lienode) A.Add(i, A.t, 1);
//		Debug(hangnode, t + t + t, lienode);
		vector<tuple<int, int, int, int, int>> g;
		F(i, 1, t) F(j, 1, t) if(mp1[i][j] && mp2[i][j]) {
//			Debug(i, j);
			g.pb({A.tot + 1, i, j, mp1[i][j], mp2[i][j]});
			A.Add(mp1[i][j], mp2[i][j], 1);
		}
		static int Flg[_];
		F(i, 1, lienode) Flg[i] = 0;
		int w = A.dinic();
//		Debug(sum, w);
		cout<<sum - w << '\n';
		for(auto v : g) {
			int a, b, c, d, e;
			tie(a, b, c, d, e) = v;
			if(A.w[a] == 0) {
				cout << C[b] << ' ' << C[c] << '\n';
				Flg[d] = Flg[e] = 1;
			}
		}
		F(i, 1, hangnode) if(!Flg[i]) {
			cout << C[Zb[i].fi] << ' ' <<C[Zb[i].se] << '\n';
		}
		F(i, t + t + t + 1, lienode) if(!Flg[i]) {
			cout << C[Zb[i].fi] << ' ' <<C[Zb[i].se] << '\n';
		}
		
	}
	// Try;
	return 0;
}

/*

1
7
1 3
6 6
4 7
2 1
6 3
4 1
2 6
3
3 4
6 4
3 1

4
7
1 3
6 6
4 7
2 1
6 3
4 1
2 6
3
3 4
6 4
3 1
2
1 1
2 2
0
3
1 1
1 3
3 3
1
1 2
3
1 1
1 3
2 3
0
*/