using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Collections.Generic;
using System.Diagnostics;
using System.Numerics;
using Enu = System.Linq.Enumerable;

class Program
{
    int N, M, Ans;
    int[][] Val, Es;
    long[] NeedMask;

    public void Solve()
    {
        N = Reader.Int();
        Val = Reader.IntTable(N);
        M = Reader.Int();
        Es = Reader.IntTable(M);
        NeedMask = new long[N];
        foreach (var e in Es) NeedMask[e[0]] |= 1L << e[1];
        Search(0, 0, 0);
        Console.WriteLine(Ans);
    }

    private void Search(int i, long need, int sum)
    {
        if (i == N) { Ans = Math.Max(Ans, sum); return; }
        if (AtMost(i, need, sum) <= Ans) return;

        if ((need >> i & 1) == 1)
        {
            Search(i + 1, need, sum);
            Search(i + 1, need | NeedMask[i], sum + Val[i][0]);
        }
        else
        {
            Search(i + 1, need | NeedMask[i], sum + Val[i][0]);
            Search(i + 1, need, sum + Val[i][1]);
        }
    }

    private int AtMost(int i, long need, int sum)
    {
        for (; i < N; i++)
            if ((need >> i & 1) == 1) sum += Val[i][0];
            else sum += Math.Max(Val[i][0], Val[i][1]);
        return sum;
    }

}


class Entry { static void Main() { new Program().Solve(); } }
class Reader
{
    private static TextReader reader = Console.In;
    private static readonly char[] separator = { ' ' };
    private static readonly StringSplitOptions op = StringSplitOptions.RemoveEmptyEntries;
    private static string[] A = new string[0];
    private static int i;
    private static void Init() { A = new string[0]; }
    public static void Set(TextReader r) { reader = r; Init(); }
    public static void Set(string file) { reader = new StreamReader(file); Init(); }
    public static bool HasNext() { return CheckNext(); }
    public static string String() { return Next(); }
    public static int Int() { return int.Parse(Next()); }
    public static long Long() { return long.Parse(Next()); }
    public static double Double() { return double.Parse(Next()); }
    public static int[] IntLine() { return Array.ConvertAll(Split(Line()), int.Parse); }
    public static int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); }
    public static int[][] IntTable(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); }
    public static string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Line()).ToArray(); }
    public static string Line() { return reader.ReadLine().Trim(); }
    private static string[] Split(string s) { return s.Split(separator, op); }
    private static string Next() { CheckNext(); return A[i++]; }
    private static bool CheckNext()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return CheckNext();
        A = Split(line);
        i = 0;
        return true;
    }
}