#include <bits/stdc++.h>
//#include <atcoder/modint>

using namespace std;
//using namespace atcoder;
using ll = long long;
//using mint = modint998244353;

int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);

    int N, x, y, ans=1e9;
    cin >> N;
    queue<pair<int, int>> que;
    vector dist(1000, vector<int>(1000, 1e9));
    for (int i=0; i<N; i++){
        cin >> x >> y;
        dist[x][y] = 0;
        que.push({x, y});
    }
    auto f=[&](int i, int j){
        return 0<=i && i<1000 && 0<=j && j<1000;
    };
    int dx[4] = {1,0,-1,0};
    int dy[4] = {0,1,0,-1};
    while(!que.empty()){
        tie(x, y) = que.front();
        que.pop();
        for (int i=0; i<4; i++){
            int nx=x+dx[i], ny=y+dy[i];
            if (f(nx, ny) && dist[nx][ny] == 1e9){
                dist[nx][ny] = dist[x][y]+1;
                que.push({nx, ny});
            }
        }
    }
    cin >> N;
    for (int i=0; i<N; i++){
        cin >> x >> y;
        ans = min(ans, dist[x][y]);
    }
    cout << ans << endl;

    return 0;
}