#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<vll> vvll;
typedef vector<vvll> vvvll;
typedef vector<pii> vpii;
typedef vector<vpii> vvpii;
typedef vector<pll> vpll;
typedef vector<vpll> vvpll;
typedef vector<pdd> vpdd;
typedef vector<vd> vvd;
#define yn(ans) printf("%s\n", (ans)?"Yes":"No");
#define YN(ans) printf("%s\n", (ans)?"YES":"NO");
    template<class T> bool chmax(T &a, T b) {
	if (a >= b) return false;
	a = b; return true;
}
template<class T> bool chmin(T &a, T b) {
	if (a <= b) return false;
	a = b; return true;
}
#define FOR(i, s, e, t) for ((i) = (s); (i) < (e); (i) += (t)) 
#define REP(i, e) for (int i = 0; i < (e); ++i) 
#define REP1(i, s, e) for (int i = (s); i < (e); ++i)
#define RREP(i, e) for (int i = (e); i >= 0; --i)
#define RREP1(i, e, s) for (int i = (e); i >= (s); --i)
#define all(v) v.begin(), v.end()
#define pb push_back
#define qb pop_back
#define pf push_front
#define qf pop_front
#define maxe max_element
#define mine min_element
ll inf = 1e18;
#define DEBUG printf("%d\n", __LINE__); fflush(stdout);
template<class T> void print(vector<T> &v, bool withSize = false) {
	if (withSize) cout << v.size() << endl;
	REP(i, v.size()) cout << v[i] << " "; 
	cout << endl;
}
mt19937_64 rng((unsigned int) chrono::steady_clock::now().time_since_epoch().count());

int __FAST_IO__ = []() {
	std::ios::sync_with_stdio(0);
	std::cin.tie(0);
	std::cout.tie(0);
	return 0;
}();

#define TESTS int t; cin >> t; while (t--)
#define TEST 
int main() {
    int N, M;
    cin >> N;
    vpii A(N);
    REP(i, N) cin >> A[i].first >> A[i].second;
    cin >> M;
    vpii B(M);
    REP(i, M) cin >> B[i].first >> B[i].second;
    
    int mx = 1000;
    vvi dis(mx, vi(mx, 1e9));
    list<vi> q;
    REP(i, N) {
        int x = A[i].first, y = A[i].second;
        dis[x][y] = 0;
        q.pb({0, x, y});
    }
    
    vvi moves = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
    while (!q.empty()) {
        auto p = q.front();
        q.qf();
        int d = p[0], x = p[1], y = p[2];
        for (auto &m: moves) {
            int nx = x + m[0], ny = y + m[1];
            if (nx >= 0 && nx < mx && ny >= 0 && ny < mx && chmin(dis[nx][ny], d + 1)) q.pb({d + 1, nx, ny});
        }
    }
    
    int ans = 1e9;
    REP(i, M) {
        int x = B[i].first, y = B[i].second;
        chmin(ans, dis[x][y]);
    }
    printf("%d\n", ans);
    return 0;
}