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


class Main {
    static ArrayList<Long>[] g;
    static void add(int a, int b, int c){
        g[a].add((long)b<<32|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>());
        for(int i=0;i<n;++i){
            b[i]=sc.nextInt();
            c[i]=sc.nextInt();
            add(0,2+i,1<<28);
            add(2+i,2+n+i,100-b[i]);
            add(2+n+i,2+i,1<<28);
            add(2+n+i,2+2*n+i,100);
            add(2+2*n+i,2+n+i,1<<28);
            add(2+2*n+i,1,100-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,1<<28);
        }
        long ans=Dinic.maximumFlow(g,0,1);
        out.println(100*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;
        }
    }
}
/* 参考: http://www.prefield.com/algorithm/graph/dinic.html */
class Dinic{
    //#define RESIDUE(s,t) (capacity[s][t]-flow[s][t])
    static final long INF=1L<<55;
    static long augment(ArrayList<Long>[] g, long[][] capacity, long[][] flow,
                       int[] level, boolean[] finished, int u, int t, long cur) {
        if (u == t || cur == 0) return cur;
        if (finished[u]) return 0;
        finished[u] = true;
        for(long e:g[u]){
            int dst=(int)(e>>>32);
            int wei=(int)e;
            if (level[dst] > level[u]) {
                long f = augment(g, capacity, flow, level, finished,
                                 dst, t, Math.min(cur, capacity[u][dst]-flow[u][dst]));
                if (f > 0) {
                    flow[u][dst] += f; flow[dst][u] -= f;
                    finished[u] = false;
                    return f;
                }
            }
        }
        return 0;
    }
    // g[i][j] = (dest)<<32|(cap)
    static long maximumFlow(ArrayList<Long>[] g, int s, int t) {
        int n = g.length;
        long[][]flow=new long[n][n], cap=new long[n][n]; // adj. matrix
        for(int u=0;u<n;++u)
            for(long e:g[u]){
                int dst=(int)(e>>>32);
                int wei=(int)e;
                cap[u][dst] += wei;
            }
        
        long total = 0;
        for (boolean cont = true; cont; ) {
            cont = false;
            int[] level=new int[n];
            Arrays.fill(level, -1);
            level[s] = 0; // make layered network
            Queue<Integer> q=new ArrayDeque<Integer>();
            q.add(s);
            for (int d = n; q.size()>0 && level[q.peek()] < d; ) {
                int u=q.poll();
                if (u == t) d = level[u];
                for(long e:g[u]){
                    int dst=(int)(e>>>32);
                    int wei=(int)e;
                    if(cap[u][dst]>flow[u][dst] && level[dst] == -1) {
                        q.add(dst);
                        level[dst]=level[u]+1;
                    }
                }
            }
            boolean[] finished=new boolean[n];// make blocking flows
            for (long f = 1; f > 0; ) {
                f = augment(g, cap, flow, level, finished, s, t, INF);
                if (f == 0) break;
                total += f; cont = true;
            }
        }
        return total;
    }
}