Problem: We have a tree with N vertices numbered 1 to N. The i-th edge in this tree connects Vertex a_i and Vertex b_i.
Consider painting each of these edges white or black. There are 2^{N-1} such ways to paint the edges. Among them, how many satisfy all of the following M restrictions?

* The i-th (1 \leq i \leq M) restriction is represented by two integers u_i and v_i, which mean that the path connecting Vertex u_i and Vertex v_i must contain at least one edge painted black.

Constraints

* 2 \leq N \leq 50
* 1 \leq a_i,b_i \leq N
* The graph given in input is a tree.
* 1 \leq M \leq \min(20,\frac{N(N-1)}{2})
* 1 \leq u_i < v_i \leq N
* If i \not= j, either u_i \not=u_j or v_i\not=v_j
* All values in input are integers.

Input

Input is given from Standard Input in the following format:


N
a_1 b_1
:
a_{N-1} b_{N-1}
M
u_1 v_1
:
u_M v_M


Output

Print the number of ways to paint the edges that satisfy all of the M conditions.

Examples

Input

3
1 2
2 3
1
1 3


Output

3


Input

2
1 2
1
1 2


Output

1


Input

5
1 2
3 2
3 4
5 3
3
1 3
2 4
2 5


Output

9


Input

8
1 2
2 3
4 3
2 5
6 3
6 7
8 6
5
2 7
3 5
1 6
2 8
7 8


Output

62

Solution (in JAVA):

Solution:
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.InputMismatchException;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

public class Main {
    private static long edgeIdsOnPath(AdjacencyList al,
                                      int u,
                                      int v,
                                      int parent) {
        for (Edge e : al.edgesFrom(u)) {
            if (e.to == parent) {
                continue;
            }
            if (e.to == v) {
                return 1L << e.id;
            }
            long r = edgeIdsOnPath(al, e.to, v, e.from);
            if (r != 0) {
                return r | (1L << e.id);
            }
        }
        return 0;
    }
    static void solve(MyScanner in, MyWriter out) {
        int n = in.nextInt();
        int[][] ab = in.nextVerticalIntArrays(2, n - 1);
        int[] a = decrement(ab[0]);
        int[] b = decrement(ab[1]);
        int m = in.nextInt();
        int[][] uv = in.nextVerticalIntArrays(2, m);
        int[] u = decrement(uv[0]);
        int[] v = decrement(uv[1]);

        List<Edge> edges = Edge.listOf(a, b);
        AdjacencyList al = AdjacencyList.forUndirectedGraph(n, edges);
        long[] conditions = new long[m];
        for (int i = 0; i < m; i++) {
            conditions[i] = edgeIdsOnPath(al, u[i], v[i], -1);
        }
        long ans = 0;
        for (int bit = 0; bit < (1 << m); bit++) {
            long union = 0;
            for (int i = 0; i < m; i++) {
                if ((bit & (1 << i)) != 0) {
                    union |= conditions[i];
                }
            }
            long count = 1L << (n - 1 - Long.bitCount(union));
            if (Long.bitCount(bit) % 2 == 0) {
                ans += count;
            } else {
                ans -= count;
            }
        }
        out.println(ans);
    }
    static final class AdjacencyList {
        private final List<List<Edge>> list;

        private AdjacencyList(List<List<Edge>> list) {
            this.list = list;
        }
        int vertexCount() {
            return list.size();
        }
        List<Edge> edgesFrom(int vertexId) {
            return list.get(vertexId);
        }
        static AdjacencyList forDirectedGraph(int vertexCount,
                                              List<Edge> edges) {
            List<List<Edge>> list =
                    new ArrayList<>(Collections.nCopies(vertexCount, null));
            list.replaceAll(e -> new ArrayList<>());
            for (Edge e : edges) {
                list.get(e.from).add(e);
            }
            return new AdjacencyList(list);
        }
        static AdjacencyList forUndirectedGraph(int vertexCount,
                                                List<Edge> edges) {
            List<List<Edge>> list =
                    new ArrayList<>(Collections.nCopies(vertexCount, null));
            list.replaceAll(e -> new ArrayList<>());
            for (Edge e : edges) {
                list.get(e.from).add(e);
                list.get(e.to).add(e.reverse());
            }
            return new AdjacencyList(list);
        }
    }
    static final class Edge {
        final int from;
        final int to;
        final long weight;
        final int id;
        Edge(int from, int to) {
            this(from, to, 1);
        }
        Edge(int from, int to, int weight) {
            this(from, to, weight, -1);
        }
        Edge(int from, int to, long weight, int id) {
            if (from < 0 || to < 0) {
                throw new IllegalArgumentException();
            }
            this.from = from;
            this.to = to;
            this.weight = weight;
            this.id = id;
        }
        int from() {
            return from;
        }
        int to() {
            return to;
        }
        long weight() {
            return weight;
        }
        Edge reverse() {
            return new Edge(to, from, weight, id);
        }
        static List<Edge> listOf(int[] from, int[] to) {
            return listOf(from, to, null);
        }
        static List<Edge> listOf(int[] from, int[] to, int[] weight) {
            if (from.length != to.length
                || (weight != null && from.length != weight.length)) {
                throw new IllegalArgumentException();
            }
            List<Edge> result = new ArrayList<>(from.length);
            for (int i = 0; i < from.length; i++) {
                result.add(new Edge(from[i],
                                    to[i],
                                    weight == null ? 1 : weight[i],
                                    i));
            }
            return result;
        }
    }
    private static int[] decrement(int[] a) {
        for (int i = 0; i < a.length; i++) {
            a[i]--;
        }
        return a;
    }
    public static void main(String[] args) {
        MyWriter w = new MyWriter(System.out);
        solve(new MyScanner(System.in), w);
        w.flush();
    }

    static final class MyScanner {
        static final int BUFFER_SIZE = 8192;
        private final InputStream in;
        private final byte[] buffer = new byte[BUFFER_SIZE];
        private int point;
        private int readLength;
        MyScanner(InputStream in) {
            this.in = in;
        }
        private byte readByte() {
            if (point < readLength) {
                byte result = buffer[point];
                point += 1;
                return result;
            }
            try {
                readLength = in.read(buffer);
            } catch (IOException e) {
                throw new AssertionError(null, e);
            }
            if (readLength == -1) {
                return -1;
            }
            point = 1;
            return buffer[0];
        }
        private static boolean isPrintableCharExceptSpace(byte c) {
            return 33 <= c && c <= 126;
        }
        public char nextChar() {
            byte c = readByte();
            while (!(c == -1 || isPrintableCharExceptSpace(c))) {
                c = readByte();
            }
            if (c == -1) {
                throw new NoSuchElementException();
            }
            return (char)c;
        }
        public String next() {
            return next(16);
        }
        public String next(int n) {
            byte c = readByte();
            while (!(c == -1 || isPrintableCharExceptSpace(c))) {
                c = readByte();
            }
            if (c == -1) {
                throw new NoSuchElementException();
            }
            StringBuilder b = new StringBuilder(n);
            do {
                b.append((char)c);
                c = readByte();
            } while (c != -1 && isPrintableCharExceptSpace(c));
            return b.toString();
        }
        public long nextLong() {
            byte c = readByte();
            while (!(c == -1 || isPrintableCharExceptSpace(c))) {
                c = readByte();
            }
            if (c == -1) {
                throw new NoSuchElementException();
            }
            boolean minus = false;
            if (c == '-') {
                minus = true;
                c = readByte();
            }
            long result = 0L;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                result = result * 10L + (c - '0');
                c = readByte();
            } while (c != -1 && isPrintableCharExceptSpace(c));
            return minus ? -result : result;
        }
        public int nextInt() {
            long n = nextLong();
            if (n < Integer.MIN_VALUE || n > Integer.MAX_VALUE) {
                throw new InputMismatchException();
            }
            return (int)n;
        }
        public double nextDouble() {
            return Double.parseDouble(next());
        }
        public int[] nextIntArray(int n) {
            int[] result = new int[n];
            for (int i = 0; i < n; i++) {
                result[i] = nextInt();
            }
            return result;
        }
        public long[] nextLongArray(int n) {
            long[] result = new long[n];
            for (int i = 0; i < n; i++) {
                result[i] = nextLong();
            }
            return result;
        }
        public char[] nextCharArray(int n) {
            char[] result = new char[n];
            for (int i = 0; i < n; i++) {
                result[i] = nextChar();
            }
            return result;
        }
        public char[][] next2dCharArray(int n, int m) {
            char[][] result = new char[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    result[i][j] = nextChar();
                }
            }
            return result;
        }
        public int[][] nextVerticalIntArrays(int arrayCount, int arrayLength) {
            int[][] result = new int[arrayCount][arrayLength];
            for (int i = 0; i < arrayLength; i++) {
                for (int j = 0; j < arrayCount; j++) {
                    result[j][i] = nextInt();
                }
            }
            return result;
        }
        public long[][] nextVerticalLongArrays(int arrayCount,
                                               int arrayLength) {
            long[][] result = new long[arrayCount][arrayLength];
            for (int i = 0; i < arrayLength; i++) {
                for (int j = 0; j < arrayCount; j++) {
                    result[j][i] = nextLong();
                }
            }
            return result;
        }
        public char[][] nextVerticalCharArrays(int arrayCount,
                                               int arrayLength) {
            char[][] result = new char[arrayCount][arrayLength];
            for (int i = 0; i < arrayLength; i++) {
                for (int j = 0; j < arrayCount; j++) {
                    result[j][i] = nextChar();
                }
            }
            return result;
        }
    }
    static final class MyWriter extends PrintWriter {
        MyWriter(OutputStream out) {
            super(out);
        }
        public void joinAndPrintln(int[] x) {
            joinAndPrintln(x, " ");
        }
        public void joinAndPrintln(int[] x, String delimiter) {
            StringBuilder b = new StringBuilder();
            if (x.length > 0) {
                b.append(x[0]);
                for (int i = 1; i < x.length; i++) {
                    b.append(delimiter).append(x[i]);
                }
            }
            println(b.toString());
        }
        public void joinAndPrintln(long[] x) {
            joinAndPrintln(x, " ");
        }
        public void joinAndPrintln(long[] x, String delimiter) {
            StringBuilder b = new StringBuilder();
            if (x.length > 0) {
                b.append(x[0]);
                for (int i = 1; i < x.length; i++) {
                    b.append(delimiter).append(x[i]);
                }
            }
            println(b.toString());
        }
        public void joinAndPrintln(Iterable<?> iterable) {
            joinAndPrintln(iterable, " ");
        }
        public void joinAndPrintln(Iterable<?> iterable, String delimiter) {
            StringBuilder b = new StringBuilder();
            for (Iterator<?> i = iterable.iterator(); i.hasNext();) {
                b.append(i.next());
                while (i.hasNext()) {
                    b.append(delimiter).append(i.next());
                }
            }
            println(b.toString());
        }
    }
}