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: #include <bits/stdc++.h>
  using namespace std;
  namespace IO {
  void setIn(string s) { freopen(s.c_str(), "r", stdin); }
  void setOut(string s) { freopen(s.c_str(), "w", stdout); }
  void setIO(string s = "") {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    if (s.size()) {
      setIn(s + ".inp");
      setOut(s + ".out");
    } else {
    }
  }
  }  // namespace IO
  using namespace IO;
  namespace Function {
  template <typename T1, typename T2>
  bool amax(T1 &a, T2 b) {
    if (a < b) {
      a = b;
      return 1;
    }
    return 0;
  }
  template <typename T1, typename T2>
  bool amin(T1 &a, T2 b) {
    if (a > b) {
      a = b;
      return 1;
    }
    return 0;
  }
  template <typename T>
  void compress(T &a) {
    sort(a.begin(), a.end());
    a.resize(unique(a.begin(), a.end()) - a.begin());
  }
  template <typename T1, typename T2, typename T3>
  int position(T1 Begin, T2 End, T3 val, bool type = 0) {
    if (type == 0) {
      return lower_bound(Begin, End, val) - Begin;
    }
    return upper_bound(Begin, End, val) - Begin;
  }
  template <typename T>
  long long sqr(T x) {
    return 1LL * x * x;
  }
  template <typename T1, typename T2>
  long long GCD(T1 a, T2 b) {
    return b == 0 ? a : GCD(b, a % b);
  }
  template <typename T1, typename T2>
  long long LCM(T1 a, T2 b) {
    return 1LL * a / GCD(a, b) * b;
  }
  }  // namespace Function
  using namespace Function;
  namespace Output {
  char End_Of_Stream = '\n';
  void print(int x) { cout << x << End_Of_Stream; }
  void print(unsigned int x) { cout << x << End_Of_Stream; }
  void print(long unsigned int x) { cout << x << End_Of_Stream; }
  void print(long long x) { cout << x << End_Of_Stream; }
  void print(unsigned long long x) { cout << x << End_Of_Stream; }
  void print(float x) { cout << x << End_Of_Stream; }
  void print(double x) { cout << x << End_Of_Stream; }
  void print(long double x) { cout << x << End_Of_Stream; }
  void print(char x) { cout << x << End_Of_Stream; }
  void print(const char *x) { cout << x << End_Of_Stream; }
  void print(string x) { cout << x << End_Of_Stream; }
  void print(bool x) { cout << x << End_Of_Stream; }
  template <typename T1, typename T2>
  void print(pair<T1, T2> a) {
    cout << a.first << " " << a.second << End_Of_Stream;
  }
  template <size_t sz>
  void print(bitset<sz> a) {
    for (int i = 0; i < sz; i++) {
      cout << a[i];
    }
    cout << End_Of_Stream;
  }
  template <typename T>
  void write(T x) {
    print(x);
  }
  template <class T, class... Ts>
  void write(T t, Ts... ts) {
    write(t);
    write(ts...);
  }
  template <class T, class... Ts>
  void print(T t, Ts... ts) {
    End_Of_Stream = ' ';
    write(t, ts...);
    cout << '\n';
    End_Of_Stream = '\n';
  }
  template <typename T>
  void print(T a) {
    for (auto it : a) {
      print(it);
    }
  }
  template <class T, class... Ts>
  void prine(T t, Ts... ts) {
    print(t, ts...);
    exit(0);
  }
  }  // namespace Output
  using namespace Output;
  const int dx[] = {1, -1, 0, 0};
  const int dy[] = {0, 0, 1, -1};
  const int INF = 1e9 + 10;
  const long long INFL = 1e18;
  const int MOD = 1e9 + 7;
  const int N = 1e5 + 10;
  int root[N][2];
  int get_root(int x, int type) {
    if (x != root[x][type]) {
      root[x][type] = get_root(root[x][type], type);
    }
    return root[x][type];
  }
  int main() {
    setIO();
    int n, m1, m2;
    cin >> n >> m1 >> m2;
    for (int i = 1; i <= n; i++) {
      root[i][0] = root[i][1] = i;
    }
    while (m1--) {
      int u, v;
      cin >> u >> v;
      root[get_root(u, 0)][0] = get_root(v, 0);
    }
    while (m2--) {
      int u, v;
      cin >> u >> v;
      root[get_root(u, 1)][1] = get_root(v, 1);
    }
    vector<pair<int, int> > res;
    for (int i = 1; i <= n; i++) {
      for (int j = i + 1; j <= n; j++) {
        int u1 = get_root(i, 0);
        int v1 = get_root(j, 0);
        int u2 = get_root(i, 1);
        int v2 = get_root(j, 1);
        if (u1 != v1 && u2 != v2) {
          res.push_back({i, j});
          root[u1][0] = v1;
          root[u2][1] = v2;
        }
      }
    }
    print(res.size());
    print(res);
    return 0;
  }
  