using System; using System.Linq; using System.Collections.Generic; using Debug = System.Diagnostics.Debug; using StringBuilder = System.Text.StringBuilder; using System.Numerics; namespace Program { public class Solver { public void Solve() { var n = sc.Integer(); var G = Enumerate(202, x => new List>()); var sum = 0; for (int i = 0; i < n; i++) { var b = sc.Integer(); var c = sc.Integer(); sum += b + c; G.AddDirectedEdge(200, i, b); G.AddDirectedEdge(i + 100, 201, c); G.AddDirectedEdge(i, i + 100, 100000); } var m = sc.Integer(); for (int i = 0; i < m; i++) { var d = sc.Integer(); var e = sc.Integer(); G.AddDirectedEdge(d, e + 100, 100000); } var mincost = Flow.GetMaxFlow(G, 200, 201); IO.Printer.Out.WriteLine(sum - mincost); } public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput()); static T[] Enumerate(int n, Func f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; } static public void Swap(ref T a, ref T b) { var tmp = a; a = b; b = tmp; } } } #region Ex namespace Program.IO { using System.IO; using System.Text; using System.Globalization; public class Printer : StreamWriter { static Printer() { Out = new Printer(Console.OpenStandardOutput()) { AutoFlush = false }; } public static Printer Out { get; set; } public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } } public Printer(System.IO.Stream stream) : base(stream, new UTF8Encoding(false, true)) { } public Printer(System.IO.Stream stream, Encoding encoding) : base(stream, encoding) { } public void Write(string format, IEnumerable source) { base.Write(format, source.OfType().ToArray()); } public void WriteLine(string format, IEnumerable source) { base.WriteLine(format, source.OfType().ToArray()); } } public class StreamScanner { public StreamScanner(Stream stream) { str = stream; } public readonly Stream str; private readonly byte[] buf = new byte[1024]; private int len, ptr; public bool isEof = false; public bool IsEndOfStream { get { return isEof; } } private byte read() { if (isEof) return 0; if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } } return buf[ptr++]; } public char Char() { byte b = 0; do b = read(); while ((b < 33 || 126 < b) && !isEof); return (char)b; } public string Scan() { var sb = new StringBuilder(); for (var b = Char(); b >= 33 && b <= 126; b = (char)read()) sb.Append(b); return sb.ToString(); } public long Long() { if (isEof) return long.MinValue; long ret = 0; byte b = 0; var ng = false; do b = read(); while (b != '-' && (b < '0' || '9' < b)); if (b == '-') { ng = true; b = read(); } for (; true; b = read()) { if (b < '0' || '9' < b) return ng ? -ret : ret; else ret = ret * 10 + b - '0'; } } public int Integer() { return (isEof) ? int.MinValue : (int)Long(); } public double Double() { return double.Parse(Scan(), CultureInfo.InvariantCulture); } private T[] enumerate(int n, Func f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(); return a; } public char[] Char(int n) { return enumerate(n, Char); } public string[] Scan(int n) { return enumerate(n, Scan); } public double[] Double(int n) { return enumerate(n, Double); } public int[] Integer(int n) { return enumerate(n, Integer); } public long[] Long(int n) { return enumerate(n, Long); } } } static class Ex { static public string AsString(this IEnumerable ie) { return new string(System.Linq.Enumerable.ToArray(ie)); } static public string AsJoinedString(this IEnumerable ie, string st = " ") { return string.Join(st, ie); } static public void Main() { var solver = new Program.Solver(); solver.Solve(); Program.IO.Printer.Out.Flush(); } } #endregion #region Edge public class Edge { public int to, rev; public T cap; public Edge(int t, int r, T _cap) { to = t; rev = r; cap = _cap; } public override string ToString() { return string.Format("{0}: Capacity {1}", to, cap); } } #endregion #region AddEdge static public partial class Flow { static public void AddDirectedEdge(this List>[] G, int from, int to, int cap) { G[from].Add(new Edge(to, G[to].Count, cap)); G[to].Add(new Edge(from, G[from].Count - 1, 0)); } static public void AddUndirectedEdge(this List>[] G, int from, int to, int cap) { G[from].Add(new Edge(to, G[to].Count, cap)); G[to].Add(new Edge(from, G[from].Count - 1, cap)); } static public void AddDirectedEdge(this List>[] G, int from, int to, long cap) { G[from].Add(new Edge(to, G[to].Count, cap)); G[to].Add(new Edge(from, G[from].Count - 1, 0)); } static public void AddUndirectedEdge(this List>[] G, int from, int to, long cap) { G[from].Add(new Edge(to, G[to].Count, cap)); G[to].Add(new Edge(from, G[from].Count - 1, cap)); } } #endregion //MaxFlow #region Dinic static public partial class Flow { static public int GetMaxFlow(List>[] G, int s, int t, int INF = 1<<30) { var n = G.Length; var level = new int[n]; var iter = new int[n]; Action bfs = p => { for (int i = 0; i < n; i++) level[i] = -1; var q = new Queue(); level[s] = 0; q.Enqueue(s); while (q.Any()) { var v = q.Dequeue(); foreach (var e in G[v]) if (e.cap > 0 && level[e.to] < 0) { level[e.to] = level[v] + 1; q.Enqueue(e.to); } } }; Func dfs = null; dfs = (v, u, f) => { if (v == t) return f; for (; iter[v] < G[v].Count; iter[v]++) { var e = G[v][iter[v]]; if (e.cap <= 0 || level[v] >= level[e.to]) continue; var d = dfs(e.to, u, Math.Min(f, e.cap)); if (d <= 0) continue; e.cap -= d; G[e.to][e.rev].cap += d; return d; } return 0; }; var flow = 0; while (true) { bfs(s); if (level[t] < 0) return flow; Array.Clear(iter, 0, iter.Length); int f; while ((f = dfs(s, t, INF)) > 0) flow += f; } } } #endregion