#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    queue<pair<int,int>> que;
    constexpr int r = 1000;
    vector<vector<int>> A(r, vector<int>(r, 1 << 30));
    for(int i = 0; i < n; i++){
        int y, x;
        cin >> y >> x;
        A[y][x] = 0;
        que.emplace(y, x);
    }
    while(!que.empty()){
        auto [y, x] = que.front();
        que.pop();
        for(int i = 0; i < 4; i++){
            int ny = y + (i == 0) - (i == 1);
            int nx = x + (i == 2) - (i == 3);
            if(ny < 0 || nx < 0 || ny >= r || nx >= r) continue;
            if(A[y][x] + 1 >= A[ny][nx])continue;
            A[ny][nx] = A[y][x] + 1;
            que.emplace(ny, nx);
        }
    }
    int m, ans = 1 << 30;
    cin >> m;
    while(m--){
        int y, x;
        cin >> y >> x;
        ans = min(ans, A[y][x]);
    }
    cout << ans << '\n';
}