#include<bits/stdc++.h>
using namespace std;
using ll=long long;
constexpr int MOD=998244353;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep2(i,l,r) for(int i=(l);i<(int)(r);i++)
#define all(v) v.begin(),v.end()

constexpr int MAX_X=1000;

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int N;
  cin>>N;
  vector dist(MAX_X,vector(MAX_X,(int)1e9));
  queue<array<int,2>>bfs;
  rep(i,N){
    int X,Y;
    cin>>X>>Y;
    dist[X][Y]=0;
    bfs.push({X,Y});
  }
  int dx[]={0,1,0,-1};
  int dy[]={-1,0,1,0};
  auto bound_ok=[&](int x,int y){
    return x>=0&&x<MAX_X&&y>=0&&y<MAX_X;
  };
  while(bfs.size()){
    auto [x,y]=bfs.front();
    bfs.pop();
    rep(i,4){
      int x2=x+dx[i],y2=y+dy[i];
      if(bound_ok(x2,y2)&&dist[x2][y2]>dist[x][y]+1){
        dist[x2][y2]=dist[x][y]+1;
        bfs.push({x2,y2});
      }
    }
  }
  int ans=1e9;
  int M;
  cin>>M;
  rep(i,M){
    int X,Y;
    cin>>X>>Y;
    ans=min(ans,dist[X][Y]);
  }
  cout<<ans<<'\n';
}