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.util.*;
  import java.io.*;
  import java.math.*;
  
  
  /**
   * @author Naitik
   * 
   */
  public class Main
  
  { 
  	 static FastReader sc=new FastReader(); 
  	 static int dp[][];
  	 static int mod=1000000007;
  	 static int mod1=998244353;
  	 static int max;
  	 static long bit[];
  //	 static long seg[];
  //	 static long fact[];
  //	 static long A[];
  	 static HashMap<Integer,Integer> map1;
  	static HashMap<Integer,Integer> map2;
  	   static PrintWriter out=new PrintWriter(System.out);
  	  public static void main(String[] args)
  {
  		  
  		   //StringBuffer sb=new StringBuffer("");
  		  int ttt=1;
  		     // ttt =i();
  	        outer :while (ttt-- > 0) 
  			{
  	        	int n=i()+1;
  	    	int m1=i();
  	    	int m2=i();
  	    	int A[]=new int[n];
  	    	int B[]=new int[n];
  	    	for(int i=1;i<n;i++) {
  	    		A[i]=i;
  	    		B[i]=i;
  	    	}
  	    	for(int i=0;i<m1;i++) {
  	    		int a=i();
  	    		int b=i();
  	    		a=find(A, a);
  	    		b=find(A, b);
  	    		if(a!=b) {
  	    			A[a]=b;
  	    		}
  	    	}
  	    	for(int i=0;i<m2;i++) {
  	    		int a=i();
  	    		int b=i();
  	    		a=find(B, a);
  	    		b=find(B, b);
  	    		if(a!=b) {
  	    			B[a]=b;
  	    		}
  	    	}
  	    	ArrayList<Integer> l1=new ArrayList<Integer>();
  	    	ArrayList<Integer> l2=new ArrayList<Integer>();
  
  	    	for(int i=1;i<n;i++) {
  	        	for(int j=i+1;j<n;j++) {
  	        		
  	        		int y=find(A, i);
  	        		int z=find(A, j);
  	        		int y1=find(B, i);
  	        		 int z1=find(B, j);
  	        		if(y==z)
  	        			continue;
  	        		
  	        		 if(y1==z1)
  		        			continue;
  	        		 l1.add(i);
  	        		 l2.add(j);
  	        		 A[y]=z;
  	        		 B[y1]=z1;
  	        		 
  	        		
  	        		 
  	        	}
  	        }
  	    	System.out.println(l1.size());
  	    	for(int i=0;i<l1.size();i++) {
  	    		out.println(l1.get(i)+" "+l2.get(i));
  	    	}
  	        	
  
  	        	
  	        	
  	        }
  	        //System.out.println(sb.toString());
  		     out.close();
  	     
  	     
  	    //CHECK FOR N=1                    //CHECK FOR M=0
          //CHECK FOR N=1                    //CHECK FOR M=0
         	//CHECK FOR N=1
         	
  		        
  		     
      }
  //	  private static void dfs(ArrayList<Integer> [] A, int i, boolean v[],int c,HashMap<Integer,Integer> map) {
  //			map.put(i, c);
  //			for(int child : A[i]) {
  //				if(!v[child]) {
  //					dfs(A, child, v,c,map);
  //				}
  //			}
  //			
  //		}
  //	  
  	   
  	  static int find(int A[],int a) {
  		  if(A[a]==a)
  			  return a;
  		  return A[a]=find(A, A[a]);
  	}
  
  static class Pair implements Comparable<Pair>
       {
      	 int x;
      	 int y;
      	 Pair(int x,int y){
      		 this.x=x;
      		 this.y=y;
      		 
      	 }
  		@Override
  		public int compareTo(Pair o) {
  			if(this.x>o.x)
  				return +1;
  			else if(this.x<o.x)
  				return -1;
  			else {
  				if(this.y>o.y)
  					return +1;
  				else if(this.y<o.y)
  					return -1;
  				else
  					return 0;
  			}
  		}
  //		public int hashCode() 
  //		{ 
  //			final int temp = 14; 
  //			int ans = 1; 
  //			ans =x*31+y*13; 
  //			return ans; 
  //		} 
  //		@Override
  //		public boolean equals(Object o) 
  //		{ 
  //			if (this == o) { 
  //				return true; 
  //			} 
  //			if (o == null) { 
  //				return false; 
  //			} 
  //			if (this.getClass() != o.getClass()) { 
  //				return false; 
  //			} 
  //			Pair other = (Pair)o; 
  //			if (this.x != other.x || this.y!=other.y) { 
  //				return false; 
  //			} 
  //			return true; 
  //		} 	
  //		
  		/* FOR TREE MAP PAIR USE */
  		
  //		public int compareTo(Pair o) {
  // 			if (x > o.x) {
  // 				return 1;
  // 			}
  // 			if (x < o.x) {
  // 				return -1;
  // 			}
  // 			if (y > o.y) {
  // 				return 1;
  // 			}
  // 			if (y < o.y) {
  // 				return -1;
  // 			}
  // 			return 0;
  // 		}
  		
       }
  //FENWICK TREE
  static void update(int i, int x){
  	for(; i < bit.length; i += (i&-i))
  		bit[i] += x;
  }
  
  static int sum(int i){
  	int ans = 0;
  	for(; i > 0; i -= (i&-i))
  		ans += bit[i];
  	return ans;
  }
  //END
  //static void add(int v) {
  //	if(!map.containsKey(v)) {
  //		map.put(v, 1);
  //	}
  //	else {
  //		map.put(v, map.get(v)+1);
  //	}
  //}
  //static void remove(int v) {
  //	if(map.containsKey(v)) {
  //		map.put(v, map.get(v)-1);
  //		if(map.get(v)==0)
  //			map.remove(v);
  //	}
  //}
  public static int upper(int A[],int k,int si,int ei)
  {
  	int l=si;
  	int u=ei;
  	int ans=-1;
  	while(l<=u) {
  		int mid=(l+u)/2;
  		if(A[mid]<=k) {
  			ans=mid;
  			l=mid+1;
  		}
  		else {
  			u=mid-1;
  		}
  	}
  	return ans;
  }
  public static int lower(int A[],int k,int si,int ei)
  {
  	int l=si;
  	int u=ei;
  	int ans=-1;
  	while(l<=u) {
  		int mid=(l+u)/2;
  		if(A[mid]<=k) {
  			l=mid+1;
  		}
  		else {
  			ans=mid;
  			u=mid-1;
  		}
  	}
  	return ans;
  	
      
  }
  static int[] copy(int A[]) {
  	int B[]=new int[A.length];
  	for(int i=0;i<A.length;i++) {
  		B[i]=A[i];
  	}
  	return B;
  }
  static long[] copy(long A[]) {
  	long B[]=new long[A.length];
  	for(int i=0;i<A.length;i++) {
  		B[i]=A[i];
  	}
  	return B;
  }
  static int[] input(int n) {
  	int A[]=new int[n];
  	   for(int i=0;i<n;i++) {
  		   A[i]=sc.nextInt();
  	   }
  	   return A;
     }
  static long[] inputL(int n) {
  	long A[]=new long[n];
  	   for(int i=0;i<n;i++) {
  		   A[i]=sc.nextLong();
  	   }
  	   return A;
     }
  static String[] inputS(int n) {
  	String A[]=new String[n];
  	   for(int i=0;i<n;i++) {
  		   A[i]=sc.next();
  	   }
  	   return A;
     }
  static long sum(int A[]) {
  	long sum=0;
  	for(int i : A) {
  		sum+=i;
  	}
  	return sum;
  }
  static long sum(long A[]) {
  	long sum=0;
  	for(long i : A) {
  		sum+=i;
  	}
  	return sum;
  }
  static void reverse(long A[]) {
  	int n=A.length;
  	long B[]=new long[n];
  	for(int i=0;i<n;i++) {
  		B[i]=A[n-i-1];
  	}
  	for(int i=0;i<n;i++)
  		A[i]=B[i];
  	
  }
  static void reverse(int A[]) {
  	int n=A.length;
  	int B[]=new int[n];
  	for(int i=0;i<n;i++) {
  		B[i]=A[n-i-1];
  	}
  	for(int i=0;i<n;i++)
  		A[i]=B[i];
  	
  }
  static void input(int A[],int B[]) {
  	   for(int i=0;i<A.length;i++) {
  		   A[i]=sc.nextInt();
  		   B[i]=sc.nextInt();
  	   }
  }
  static int[][] input(int n,int m){
  	int A[][]=new int[n][m];
  	for(int i=0;i<n;i++) {
  		for(int j=0;j<m;j++) {
  			A[i][j]=i();
  		}
  	}
  	return A;
  }
  static char[][] charinput(int n,int m){
  	char A[][]=new char[n][m];
  	for(int i=0;i<n;i++) {
  		String s=s();
  		for(int j=0;j<m;j++) {
  			A[i][j]=s.charAt(j);
  		}
  	}
  	return A;
  }
  
  static int max(int A[]) {
  	int max=Integer.MIN_VALUE;
  	for(int i=0;i<A.length;i++) {
  		max=Math.max(max, A[i]);
  	}
  	return max;
  }
  static int min(int A[]) {
  	int min=Integer.MAX_VALUE;
  	for(int i=0;i<A.length;i++) {
  		min=Math.min(min, A[i]);
  	}
  	return min;
  }
  static long max(long A[]) {
  	long max=Long.MIN_VALUE;
  	for(int i=0;i<A.length;i++) {
  		max=Math.max(max, A[i]);
  	}
  	return max;
  }
  static long min(long A[]) {
  	long min=Long.MAX_VALUE;
  	for(int i=0;i<A.length;i++) {
  		min=Math.min(min, A[i]);
  	}
  	return min;
  }
  static long [] prefix(long A[]) {
  	long p[]=new long[A.length];
  	p[0]=A[0];
  	for(int i=1;i<A.length;i++)
  		p[i]=p[i-1]+A[i];
  	return p;
  }
  static long [] prefix(int A[]) {
  	long p[]=new long[A.length];
  	p[0]=A[0];
  	for(int i=1;i<A.length;i++)
  		p[i]=p[i-1]+A[i];
  	return p;
  }
  static long [] suffix(long A[]) {
  	long p[]=new long[A.length];
  	p[A.length-1]=A[A.length-1];
  	for(int i=A.length-2;i>=0;i--)
  		p[i]=p[i+1]+A[i];
  	return p;
  }
  static long [] suffix(int A[]) {
  	long p[]=new long[A.length];
  	p[A.length-1]=A[A.length-1];
  	for(int i=A.length-2;i>=0;i--)
  		p[i]=p[i+1]+A[i];
  	return p;
  }
  static void fill(int dp[]) {
  	Arrays.fill(dp, -1);
  }
  static void fill(int dp[][]) {
  	for(int i=0;i<dp.length;i++)
  	Arrays.fill(dp[i], -1);
  }
  static void fill(int dp[][][]) {
  	for(int i=0;i<dp.length;i++) {
  		for(int j=0;j<dp[0].length;j++) {
  			Arrays.fill(dp[i][j],-1);
  		}
  	}
  }
  static void fill(int dp[][][][]) {
  	for(int i=0;i<dp.length;i++) {
  		for(int j=0;j<dp[0].length;j++) {
  			for(int k=0;k<dp[0][0].length;k++) {
  			Arrays.fill(dp[i][j][k],-1);
  			}
  		}
  	}
  }
  static void fill(long dp[]) {
  	Arrays.fill(dp, -1);
  }
  static void fill(long dp[][]) {
  	for(int i=0;i<dp.length;i++)
  	Arrays.fill(dp[i], -1);
  }
  static void fill(long dp[][][]) {
  	for(int i=0;i<dp.length;i++) {
  		for(int j=0;j<dp[0].length;j++) {
  			Arrays.fill(dp[i][j],-1);
  		}
  	}
  }
  static void fill(long dp[][][][]) {
  	for(int i=0;i<dp.length;i++) {
  		for(int j=0;j<dp[0].length;j++) {
  			for(int k=0;k<dp[0][0].length;k++) {
  			Arrays.fill(dp[i][j][k],-1);
  			}
  		}
  	}
  }
  static int min(int a,int b) {
  	return Math.min(a, b);
  }
  static int min(int a,int b,int c) {
  	return Math.min(a, Math.min(b, c));
  }
  static int min(int a,int b,int c,int d) {
  	return Math.min(a, Math.min(b, Math.min(c, d)));
  }
  static int max(int a,int b) {
  	return Math.max(a, b);
  }
  static int max(int a,int b,int c) {
  	return Math.max(a, Math.max(b, c));
  }
  static int max(int a,int b,int c,int d) {
  	return Math.max(a, Math.max(b, Math.max(c, d)));
  }
  static long min(long a,long b) {
  	return Math.min(a, b);
  }
  static long min(long a,long b,long c) {
  	return Math.min(a, Math.min(b, c));
  }
  static long min(long a,long b,long c,long d) {
  	return Math.min(a, Math.min(b, Math.min(c, d)));
  }
  static long max(long a,long b) {
  	return Math.max(a, b);
  }
  static long max(long a,long b,long c) {
  	return Math.max(a, Math.max(b, c));
  }
  static long max(long a,long b,long c,long d) {
  	return Math.max(a, Math.max(b, Math.max(c, d)));
  }
  
  static long power(long x, long y, long p)
  {
  
  	if(y==0)
  		return 1;
  	if(x==0)
  		return 0;
      long res = 1;
      x = x % p;
  
      while (y > 0) {
  
          if (y % 2 == 1)
              res = (res * x) % p;
  
          y = y >> 1; 
          x = (x * x) % p;
      }
  
      return res;
  }
  static void print(int A[]) {
  	for(int i : A) {
  		System.out.print(i+" ");
  	}
  	System.out.println();
  }
  static void print(long A[]) {
  	for(long i : A) {
  		System.out.print(i+" ");
  	}
  	System.out.println();
  }
  static long mod(long x) {
  	  return ((x%mod + mod)%mod);
  }
  static String reverse(String s) {
  	StringBuffer p=new StringBuffer(s);
  	p.reverse();
  	return p.toString();
  }
  
       static int i() {
      	 return sc.nextInt();
       }
       static String s() {
      	 return sc.next();
       }
       static long l() {
      	 return sc.nextLong();
       }  
       static void sort(int[] A){
          int n = A.length;
          Random rnd = new Random();
          for(int i=0; i<n; ++i){
              int tmp = A[i];
              int randomPos = i + rnd.nextInt(n-i);
              A[i] = A[randomPos];
              A[randomPos] = tmp;
          }
          Arrays.sort(A);
       }
       static void sort(long[] A){
  	        int n = A.length;
  	        Random rnd = new Random();
  	        for(int i=0; i<n; ++i){
  	            long tmp = A[i];
  	            int randomPos = i + rnd.nextInt(n-i);
  	            A[i] = A[randomPos];
  	            A[randomPos] = tmp;
  	        }
  	        Arrays.sort(A);
  	     }
    static String sort(String s) {
   	 Character ch[]=new Character[s.length()];
   	 for(int i=0;i<s.length();i++) {
   		 ch[i]=s.charAt(i);
   	 }
   	 Arrays.sort(ch);
   	 StringBuffer st=new StringBuffer("");
   	 for(int i=0;i<s.length();i++) {
   		 st.append(ch[i]);
   	 }
   	 return st.toString();
    }
    static HashMap<Integer,Integer> hash(int A[]){
  	  HashMap<Integer,Integer> map=new HashMap<Integer, Integer>();
  	  for(int i : A) {
  		  if(map.containsKey(i)) {
  			  map.put(i, map.get(i)+1);
  		  }
  		  else {
  			  map.put(i, 1);
  		  }
  	  }
  	  return map;
    }
    static TreeMap<Integer,Integer> tree(int A[]){
  	  TreeMap<Integer,Integer> map=new TreeMap<Integer, Integer>();
  	  for(int i : A) {
  		  if(map.containsKey(i)) {
  			  map.put(i, map.get(i)+1);
  		  }
  		  else {
  			  map.put(i, 1);
  		  }
  	  }
  	  return map;
    }
       static boolean prime(int n) 
  	    { 
  	        if (n <= 1) 
  	            return false; 
  	        if (n <= 3) 
  	            return true; 
  	        if (n % 2 == 0 || n % 3 == 0) 
  	            return false; 
  	        double sq=Math.sqrt(n);
  	  
  	        for (int i = 5; i <= sq; i = i + 6) 
  	            if (n % i == 0 || n % (i + 2) == 0) 
  	                return false; 
  	        return true; 
  	    } 
       static boolean prime(long n) 
  	    { 
  	        if (n <= 1) 
  	            return false; 
  	        if (n <= 3) 
  	            return true; 
  	        if (n % 2 == 0 || n % 3 == 0) 
  	            return false; 
  	        double sq=Math.sqrt(n);
  	  
  	        for (int i = 5; i <= sq; i = i + 6) 
  	            if (n % i == 0 || n % (i + 2) == 0) 
  	                return false; 
  	        return true; 
  	    } 
       static int gcd(int a, int b) 
       { 
           if (a == 0) 
               return b; 
           return gcd(b % a, a); 
       } 
       static long gcd(long a, long b) 
       { 
           if (a == 0) 
               return b; 
           return gcd(b % a, a); 
       } 
       
          
      static class FastReader 
      { 
          BufferedReader br; 
          StringTokenizer st; 
    
          public FastReader() 
          { 
              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; 
          } 
      } 
  } 
  
  
  
  