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.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.StringTokenizer;
  
  public class Solve {
  
  	static int mod = 1000_000_000 + 7;
  	static long INF = 1000_000_000_000_000L + 100;
  
  	public static void main(String[] args) throws Exception {
  		Scanner sc = new Scanner();
  		PrintWriter pw = new PrintWriter(System.out);
  
  		int n = sc.nextInt();
  		int m1 = sc.nextInt();
  		int m2 = sc.nextInt();
  		UnionFind U1 = new UnionFind(n + 1);
  		UnionFind U2 = new UnionFind(n + 1);
  
  		for (int i = 0; i < m1; i++) {
  			int u = sc.nextInt();
  			int v = sc.nextInt();
  			U1.unionSet(u, v);
  		}
  
  		for (int i = 0; i < m2; i++) {
  			int u = sc.nextInt();
  			int v = sc.nextInt();
  			U2.unionSet(u, v);
  		}
  
  		ArrayList<Pair> ans = new ArrayList<Pair>();
  		for (int i = 1; i <= n; i++) {
  			for (int j = i + 1; j <= n; j++) {
  				int u = i;
  				int v = j;
  
  				if (U1.isSameSet(u, v) || U2.isSameSet(u, v)) {
  					continue;
  				}
  
  				ans.add(new Pair(u, v));
  				U1.unionSet(u, v);
  				U2.unionSet(u, v);
  
  			}
  
  		}
  		pw.println(ans.size());
  		for (Pair p : ans) {
  			pw.println(p.x + " " + p.y);
  		}
  
  		pw.flush();
  
  	}
  
  	static long LowerBound(int a[], int x, int start) { // x is the target value or key
  		int l = start, r = a.length;
  		while (l + 1 < r) {
  			int m = (l + r) >>> 1;
  			if (a[m] >= x)
  				r = m;
  			else
  				l = m;
  		}
  		return r;
  	}
  
  	static long UpperBound(int a[], int x, int start) {// x is the key or target value
  		int l = start, r = a.length;
  		while (l + 1 < r) {
  			int m = (l + r) >>> 1;
  			if (a[m] <= x)
  				l = m;
  			else
  				r = m;
  		}
  		return l + 1;
  	}
  
  	static public boolean[] sieve(int n) {
  		boolean prime[] = new boolean[n + 1];
  		for (int i = 0; i <= n; i++)
  			prime[i] = true;
  
  		for (int p = 2; p * p <= n; p++) {
  			// If prime[p] is not changed, then it is a
  			// prime
  			if (prime[p] == true) {
  				// Update all multiples of p
  				for (int i = p * p; i <= n; i += p)
  					prime[i] = false;
  			}
  		}
  		return prime;
  
  	}
  
  	public static ArrayList<Integer> primeFactors(int n) {
  		ArrayList<Integer> set = new ArrayList<Integer>();
  
  		// Print the number of 2s that divide n
  		while (n % 2 == 0) {
  			n /= 2;
  			set.add(2);
  		}
  
  		// n must be odd at this point. So we can
  		// skip one element (Note i = i +2)
  		for (int i = 3; i * i <= n; i += 2) {
  			// While i divides n, print i and divide n
  			while (n % i == 0) {
  				n /= i;
  				set.add(i);
  			}
  		}
  
  		if (n > 1)
  			set.add(n);
  
  		return set;
  
  	}
  
  	static int gcd(int a, int b) {
  		if (a == 0)
  			return b;
  		if (b == 0)
  			return a;
  
  		return gcd(b, a % b);
  
  	}
  
  	public static int[] swap(int data[], int left, int right) {
  
  		// Swap the data
  		int temp = data[left];
  		data[left] = data[right];
  		data[right] = temp;
  
  		// Return the updated array
  		return data;
  	}
  
  	static long nCrModp(int n, int r, int p) {
  		if (r > n - r)
  			r = n - r;
  
  		// The array C is going to store last
  		// row of pascal triangle at the end.
  		// And last entry of last row is nCr
  		int C[] = new int[r + 1];
  
  		C[0] = 1; // Top row of Pascal Triangle
  
  		// One by constructs remaining rows of Pascal
  		// Triangle from top to bottom
  		for (int i = 1; i <= n; i++) {
  
  			// Fill entries of current row using previous
  			// row values
  			for (int j = Math.min(i, r); j > 0; j--)
  
  				// nCj = (n-1)Cj + (n-1)C(j-1);
  				C[j] = (C[j] + C[j - 1]) % p;
  		}
  		return C[r];
  	}
  
  	static void sort(int[] a) {
  		ArrayList<Integer> l = new ArrayList<>();
  		for (int i : a)
  			l.add(i);
  		Collections.sort(l);
  		for (int i = 0; i < a.length; i++)
  			a[i] = l.get(i);
  	}
  
  }
  
  class Pair {
  	int x, y;
  
  	Pair(int x, int y) {
  		this.x = x;
  		this.y = y;
  	}
  
  }
  
  class SegTree {
  	int leftmost, rightmost, sum;
  	SegTree lChild, rChild;
  
  	public SegTree(int leftmost, int rightmost) {
  		this.leftmost = leftmost;
  		this.rightmost = rightmost;
  	}
  
  	public void update(int index, int val) {
  		sum++;
  		if (leftmost == rightmost) {
  			return;
  		}
  		if (lChild == null)
  			makeKids();
  		if (index <= lChild.rightmost)
  			lChild.update(index, val);
  		else
  			rChild.update(index, val);
  	}
  
  	public void makeKids() {
  		int mid = (leftmost + rightmost) / 2;
  		lChild = new SegTree(leftmost, mid);
  		rChild = new SegTree(mid + 1, rightmost);
  	}
  
  	public int query(int l, int r) {
  		if (l <= leftmost && r >= rightmost)
  			return sum;
  		if (l > rightmost || r < leftmost)
  			return 0;
  		if (lChild == null)
  			return 0;
  		return lChild.query(l, r) + rChild.query(l, r);
  	}
  }
  
  class UnionFind {
  	int[] p, rank, setSize;
  	int numSets;
  
  	public UnionFind(int N) {
  		p = new int[numSets = N];
  		rank = new int[N];
  		setSize = new int[N];
  		for (int i = 0; i < N; i++) {
  			p[i] = i;
  			setSize[i] = 1;
  		}
  	}
  
  	public int findSet(int i) {
  		return p[i] == i ? i : (p[i] = findSet(p[i]));
  	}
  
  	public boolean isSameSet(int i, int j) {
  		return findSet(i) == findSet(j);
  	}
  
  	public void unionSet(int i, int j) {
  		if (isSameSet(i, j))
  			return;
  		numSets--;
  		int x = findSet(i), y = findSet(j);
  		if (rank[x] > rank[y]) {
  			p[y] = x;
  			setSize[x] += setSize[y];
  		} else {
  			p[x] = y;
  			setSize[y] += setSize[x];
  			if (rank[x] == rank[y])
  				rank[y]++;
  		}
  	}
  
  	public int numDisjointSets() {
  		return numSets;
  	}
  
  	public int sizeOfSet(int i) {
  		return setSize[findSet(i)];
  	}
  }
  
  class Scanner {
  	BufferedReader br;
  	StringTokenizer st;
  
  	Scanner() {
  		br = new BufferedReader(new InputStreamReader(System.in));
  	}
  
  	String next() throws IOException {
  		while (st == null || !st.hasMoreElements())
  			st = new StringTokenizer(br.readLine());
  		return st.nextToken();
  	}
  
  	int nextInt() throws NumberFormatException, IOException {
  		return Integer.parseInt(next());
  	}
  
  	int[] nextIntArray(int n) throws NumberFormatException, IOException {
  		int a[] = new int[n];
  		for (int i = 0; i < n; i++)
  			a[i] = Integer.parseInt(next());
  		return a;
  	}
  
  	long nextLong() throws NumberFormatException, IOException {
  		return Long.parseLong(next());
  	}
  
  	long[] nextLongArray(int n) throws NumberFormatException, IOException {
  		long a[] = new long[n];
  		for (int i = 0; i < n; i++)
  			a[i] = Long.parseLong(next());
  		return a;
  	}
  
  	double nextDouble() throws NumberFormatException, IOException {
  		return Double.parseDouble(next());
  	}
  }