description: This is the easy version of the problem. The only difference between the two versions is the constraint on n. You can make hacks only if all versions of the problem are solved.
  
  A forest is an undirected graph without cycles (not necessarily connected).
  
  Mocha and Diana are friends in Zhijiang, both of them have a forest with nodes numbered from 1 to n, and they would like to add edges to their forests such that: 
  
    * After adding edges, both of their graphs are still forests. 
    * They add the same edges. That is, if an edge (u, v) is added to Mocha's forest, then an edge (u, v) is added to Diana's forest, and vice versa. 
  
  
  
  Mocha and Diana want to know the maximum number of edges they can add, and which edges to add.
  
  Input
  
  The first line contains three integers n, m_1 and m_2 (1 ≤ n ≤ 1000, 0 ≤ m_1, m_2 < n) — the number of nodes and the number of initial edges in Mocha's forest and Diana's forest.
  
  Each of the next m_1 lines contains two integers u and v (1 ≤ u, v ≤ n, u ≠ v) — the edges in Mocha's forest.
  
  Each of the next m_2 lines contains two integers u and v (1 ≤ u, v ≤ n, u ≠ v) — the edges in Diana's forest.
  
  Output
  
  The first line contains only one integer h, the maximum number of edges Mocha and Diana can add (in each forest).
  
  Each of the next h lines contains two integers u and v (1 ≤ u, v ≤ n, u ≠ v) — the edge you add each time.
  
  If there are multiple correct answers, you can print any one of them.
  
  Examples
  
  Input
  
  
  3 2 2
  1 2
  2 3
  1 2
  1 3
  
  
  Output
  
  
  0
  
  
  Input
  
  
  5 3 2
  5 4
  2 1
  4 3
  4 3
  1 4
  
  
  Output
  
  
  1
  2 4
  
  
  Input
  
  
  8 1 2
  1 7
  2 6
  1 5
  
  
  Output
  
  
  5
  5 2
  2 3
  3 4
  4 7
  6 8
  
  Note
  
  In the first example, we cannot add any edge.
  
  In the second example, the initial forests are as follows.
  
  <image>
  
  We can add an edge (2, 4).
  
  <image>
solution: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.util.StringTokenizer;
  import java.io.IOException;
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author xwchen
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          TaskD solver = new TaskD();
          solver.solve(1, in, out);
          out.close();
      }
  
      static class TaskD {
          public void solve(int testNumber, InputReader in, PrintWriter out) {
              int n = in.nextInt();
              int m1 = in.nextInt();
              int m2 = in.nextInt();
              DisjointSet ds1 = new DisjointSet(n);
              DisjointSet ds2 = new DisjointSet(n);
              for (int i = 0; i < m1; i++) {
                  int u = in.nextInt();
                  int v = in.nextInt();
                  ds1.union(u, v);
              }
              for (int i = 0; i < m2; i++) {
                  int u = in.nextInt();
                  int v = in.nextInt();
                  ds2.union(u, v);
              }
              int[] l = new int[n];
              int[] r = new int[n];
              int len = 0;
              for (int i = 1; i <= n; i++) {
                  for (int j = i + 1; j <= n; j++) {
                      int dx1 = ds1.find(i);
                      int dy1 = ds1.find(j);
                      int dx2 = ds2.find(i);
                      int dy2 = ds2.find(j);
                      if (dx1 != dy1 && dx2 != dy2) {
                          l[len] = i;
                          r[len] = j;
                          ++len;
                          ds1.union(i, j);
                          ds2.union(i, j);
                      }
                  }
              }
              out.println(len);
              for (int i = 0; i < len; i++) {
                  out.println(l[i] + " " + r[i]);
              }
          }
  
      }
  
      static class DisjointSet {
          private int[] set;
          private int[] size;
  
          public DisjointSet(int n) {
              set = new int[n + 1];
              size = new int[n + 1];
              for (int i = 1; i <= n; ++i) {
                  set[i] = i;
                  size[i] = 1;
              }
          }
  
          public int find(int x) {
              return set[x] == x ? x : (set[x] = find(set[x]));
          }
  
          public void union(int x, int y) {
              int sx = find(x);
              int sy = find(y);
              if (sx != sy) {
                  set[sy] = sx;
                  size[sx] += size[sy];
              }
          }
  
      }
  
      static class InputReader {
          private BufferedReader reader;
          private StringTokenizer tokenizer = new StringTokenizer("");
  
          public InputReader(InputStream inputStream) {
              this.reader = new BufferedReader(
                      new InputStreamReader(inputStream));
          }
  
          public String next() {
              while (!tokenizer.hasMoreTokens()) {
                  try {
                      tokenizer = new StringTokenizer(reader.readLine());
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              }
              return tokenizer.nextToken();
          }
  
          public int nextInt() {
              return Integer.parseInt(next());
          }
  
      }
  }
  
  