output_description: For each query, print "yes" if $t$ is reachable from $s$ through the social
  network, "no" otherwise.
input_description: In the first line, two integer $n$ and $m$ are given. $n$ is the number of
  users in the SNS and $m$ is the number of relations in the SNS. The users in
  the SNS are identified by IDs $0, 1, ..., n-1$.
  
  In the following $m$ lines, the relations are given. Each relation is given by
  two integers $s$ and $t$ that represents $s$ and $t$ are friends (and
  reachable each other).
  
  In the next line, the number of queries $q$ is given. In the following $q$
  lines, $q$ queries are given respectively. Each query consists of two integers
  $s$ and $t$ separated by a space character.
attempt: from sys import stdin
  
  
  def read_graph(n, k):
      A = [[] for _ in range(n)]
      for _ in range(k):
          line = stdin.readline().strip().split()
          A[int(line[0])].append(int(line[1]))
          A[int(line[1])].append(int(line[0]))
      return A
  
  
  def dfs_ctrl(n, A, s, t):
      color = ["WHITE"] * n
      d = [0] * n
      f = [0] * n
      time = 0
  
      def dfs(u):
          nonlocal color
          nonlocal time
          color[u] = "GRAY"
          time += 1
          d[u] = time
  
          for v in A[u]:
              if color[v] == "WHITE":
                  dfs(v)
          color[u] = "BLACK"
          time += 1
          f[u] = time
  
      dfs(s)
      if d[t] != 0:
          print("yes")
      else:
          print("no")
  
  
  def read_and_print_connection(m):
      for _ in range(m):
          line = stdin.readline().strip().split()
          s = int(line[0])
          t = int(line[1])
          dfs_ctrl(n, A, s, t)
  
  
  n, k = [int(i) for i in input().split()]
  A = read_graph(n, k)
  m = int(input())
  read_and_print_connection(m)
  
problem_description: Connected Components
  
  Write a program which reads relations in a SNS (Social Network Service), and
  judges that given pairs of users are reachable each other through the network.
samples: [{"input": "9\n    0 1\n    0 2\n    3 4\n    5 7\n    5 6\n    6 7\n    6 8\n    7 8\n    8 9\n    3\n    0 1\n    5 9\n    1 3", "output": "yes\n    yes\n    no"}]