using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace B
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<Int32, Int32> dict = new Dictionary<Int32, Int32>();

            Int32 n = Int32.Parse(Console.ReadLine());
            for (int i = 0; i < n; i++)
            {
                Int32[] input = Console.ReadLine().Split(' ').Select(Int32.Parse).ToArray();
                dict[input[0]] = input[1];
            }

            Int32 m = Int32.Parse(Console.ReadLine());
            for (int i = 0; i < m; i++)
            {
                Int32[] input = Console.ReadLine().Split(' ').Select(Int32.Parse).ToArray();
                Int32 b = input[0];
                Int32 y = input[1];
                if (!dict.ContainsKey(b))
                {
                    dict[b] = y;
                    continue;
                }

                if (dict[b] < y)
                    dict[b] = y;
            }

            Int64 result = 0;
            foreach (Int32 value in dict.Values)
            {
                result += value;
            }

            Console.WriteLine(result);
        }
    }
}