import java.io.*;
import java.util.*;


class Main {
    static final int I=100000;
    static ArrayList<Long>[] g;
    static int[][]mat;
    static void add(int a, int b, int c){
        g[a].add((long)b<<32|c);
        mat[a][b]+=c;
    }
    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));
        int n=sc.nextInt();
        int[]b=new int[n],c=new int[n];
        g=new ArrayList[3*n+2];
        Arrays.setAll(g,x->new ArrayList<Long>());
        mat=new int[3*n+2][3*n+2];
        for(int i=0;i<n;++i){
            b[i]=sc.nextInt();
            c[i]=sc.nextInt();
            add(0,2+n+i,150-b[i]);
            add(2+n+i,2+2*n+i,150);
            add(2+2*n+i,2+n+i,I);
            add(2+2*n+i,1,150-c[i]);
        }
        int m=sc.nextInt();
        for(int i=0;i<m;++i){
            int d=sc.nextInt();
            int e=sc.nextInt();
            add(2+2*n+e,2+n+d,I);
        }
        MaxFlow mf = new MaxFlow();
        long ans=mf.fordFulkerson(mat,0,1);
        out.println(150*n-ans);
        out.close();
    }
    // http://codeforces.com/blog/entry/7018
    //-----------PrintWriter for faster output---------------------------------
    public static PrintWriter out;
    //-----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;
        public MyScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() {
            return Long.parseLong(next());
        }
        double nextDouble() {
            return Double.parseDouble(next());
        }
        String nextLine(){
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
        int[] nextIntArray(int n){
            int[]r=new int[n];
            for(int i=0;i<n;++i)r[i]=nextInt();
            return r;
        }
    }
}
class MaxFlow
{
 
    /* Returns true if there is a path from source 's' to sink
      't' in residual graph. Also fills parent[] to store the
      path */
    boolean bfs(int rGraph[][], int s, int t, int parent[])
    {
        // Create a visited array and mark all vertices as not
        // visited
        int V=rGraph.length;
        boolean visited[] = new boolean[V];
        for(int i=0; i<V; ++i)
            visited[i]=false;
 
        // Create a queue, enqueue source vertex and mark
        // source vertex as visited
        LinkedList<Integer> queue = new LinkedList<Integer>();
        queue.add(s);
        visited[s] = true;
        parent[s]=-1;
 
        // Standard BFS Loop
        while (queue.size()!=0)
        {
            int u = queue.poll();
 
            for (int v=0; v<V; v++)
            {
                if (visited[v]==false && rGraph[u][v] > 0)
                {
                    queue.add(v);
                    parent[v] = u;
                    visited[v] = true;
                }
            }
        }
 
        // If we reached sink in BFS starting from source, then
        // return true, else false
        return (visited[t] == true);
    }
 
    // Returns tne maximum flow from s to t in the given graph
    int fordFulkerson(int graph[][], int s, int t)
    {
        int u, v;
 
        // Create a residual graph and fill the residual graph
        // with given capacities in the original graph as
        // residual capacities in residual graph
 
        // Residual graph where rGraph[i][j] indicates
        // residual capacity of edge from i to j (if there
        // is an edge. If rGraph[i][j] is 0, then there is
        // not)
        int V=graph.length;
        int rGraph[][] = new int[V][V];
 
        for (u = 0; u < V; u++)
            for (v = 0; v < V; v++)
                rGraph[u][v] = graph[u][v];
 
        // This array is filled by BFS and to store path
        int parent[] = new int[V];
 
        int max_flow = 0;  // There is no flow initially
 
        // Augment the flow while tere is path from source
        // to sink
        while (bfs(rGraph, s, t, parent))
        {
            // Find minimum residual capacity of the edhes
            // along the path filled by BFS. Or we can say
            // find the maximum flow through the path found.
            int path_flow = Integer.MAX_VALUE;
            for (v=t; v!=s; v=parent[v])
            {
                u = parent[v];
                path_flow = Math.min(path_flow, rGraph[u][v]);
            }
 
            // update residual capacities of the edges and
            // reverse edges along the path
            for (v=t; v != s; v=parent[v])
            {
                u = parent[v];
                rGraph[u][v] -= path_flow;
                rGraph[v][u] += path_flow;
            }
 
            // Add path flow to overall flow
            max_flow += path_flow;
        }
 
        // Return the overall flow
        return max_flow;
    }
}