493C

#include <bits/stdc++.h>
#include <stdio.h>

using namespace std;



int main()
{
    int n, m;
    scanf("%d", &n);
    long long x;
    vector<pair<long long, int> > v;
    for(int i=0; i < n; i++)
    {
        scanf("%d", &x);
        v.push_back(make_pair(x, 0));
    }

    scanf("%d", &m);
    for(int i=0; i < m; i++)
    {
        scanf("%d", &x);
        v.push_back(make_pair(x, 1));
    }
    //for(int i=0; i<v.size();i++) cout << v[i].first << " " << v[i].second << endl;
    sort(v.begin(), v.end());
   // for(int i=0; i<v.size();i++) cout << v[i].first << " " << v[i].second << endl;
    long long a=0, b=0, best=-(1<<31), besta=-(1<<31), bestb=-(1<<31), nbest=-(1<<31);
    //cout << "best " << best << endl;
    //cout << best << endl;
    for(int i=0;i < v.size(); )
    {
        nbest = ( (n-a)*3 + a*2 ) - ( (m - b) * 3 + b * 2 );
        //cout << "nbest = " << nbest << endl;
        //cout << "nbest " << nbest << endl;
        if((best < nbest) || (best == nbest && besta < (n-a)*3 + a*2 ) )
        {
            besta = (n - a)*3 + a*2;
            best = nbest;
            bestb = (m - b) * 3 + b * 2;
             // cout << "ZMENA " << best << " " << besta << " " << bestb << endl;
        }
        int k = 0;
        //for(;v[i].first == v[i+1].first && i < n + m - 1; i++)
        if(v[i].first > i)
        {
            if(v[i].second == 0)
                a++;
            else
                b++;
            k++;
        }
        i++;
    }
    nbest = n*2 - m*2;
    //cout << "nbest = " << nbest << endl;
        if((best < nbest) || (best == nbest && besta < (n-a)*3 + a*2 ) )
        {
            besta = (n - a)*3 + a*2;
            best = nbest;
            bestb = (m - b) * 3 + b * 2;
            //cout << "ZMENA " << best << " " << besta << " " << bestb << endl;
        }
    cout << besta << ":" << bestb << endl;
    return 0;
}