#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
istream &operator>>(istream &is, modint &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint &a) { return os << a.val(); }
istream &operator>>(istream &is, modint998244353 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint998244353 &a) { return os << a.val(); }
istream &operator>>(istream &is, modint1000000007 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint1000000007 &a) { return os << a.val(); } 

typedef long long ll;
typedef vector<vector<int>> Graph;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define FOR(i,l,r) for (int i = l;i < (int)(r); i++)
#define rep(i,n) for (int i = 0;i < (int)(n); i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define my_sort(x) sort(x.begin(), x.end())
#define my_max(x) *max_element(all(x))
#define my_min(x) *min_element(all(x))
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = (1<<30) - 1;
const ll LINF = (1LL<<62) - 1;
const int MOD = 998244353;
const int MOD2 = 1e9+7;
const double PI = acos(-1);
vector<int> di = {1,0,-1,0};
vector<int> dj = {0,1,0,-1};

#ifdef LOCAL
#  include <debug_print.hpp>
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

const int L = 1000;

int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    
    int N; cin >> N;

    vector dist(L, vector<int>(L, INF));
    queue<pii> Q;
    rep(i, N){
        int x, y; cin >> x >> y;
        dist[x][y] = 0;
        Q.push(make_pair(x, y));
    }

    while(!Q.empty()){
        auto [i, j] = Q.front(); Q.pop();
        rep(d, 4){
            int ni = i + di[d], nj = j + dj[d];
            if(ni < 0 || ni >= L || nj < 0 || nj >= L) continue;
            if(dist[ni][nj] != INF) continue;
            dist[ni][nj] = dist[i][j] + 1;
            Q.push(make_pair(ni, nj));
        }
    }

    int ans = INF;
    int M; cin >> M;
    rep(i, M){
        int z, w; cin >> z >> w;
        chmin(ans, dist[z][w]);
    }
    cout << ans << endl;
}