#include <iostream>
#include <map>
#include <bits/stdc++.h>
using namespace std;

int main()
{
    int a,b;
    cin>>a;
    int x[a];
    for(int i=0;i<a;i++)
    {
        cin>>x[i];
    }
    sort(x,x +a);
    cin>>b;
    int y[b];
    for(int j=0;j<b;j++)
    {
        cin>>y[j];
    }
    sort(y,y +b);
    int l=0;
    int r=b-1;
    int mid;
    int najmal=2000000000;
    int broj=-1;
    for(int i=0;i<a;i++)
    {
        l=0;
        r=b-1;
        while(l<=r)
        {
            mid=(r+l)/2;

        if(y[mid]<x[i])
        {
            l=mid+1;
        }
        if(y[mid]>=x[i])
        {
            if(najmal > y[mid]-x[i])
            {
                najmal=y[mid]-x[i];

                broj=x[i];

            }
            if(najmal == y[mid] - x[i] and broj < x[i]) {
                broj = x[i];
            }

            r=mid-1;
        }
        }
//        cout << x[i] /<< " " << najmal << endl;

    }
    cout<<broj << endl;
    return 0;
}