output_description: Print the number of ways to paint the edges that satisfy all of the M
  conditions.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      a_1 b_1
      :
      a_{N-1} b_{N-1}
      M
      u_1 v_1
      :
      u_M v_M
attempt: from collections import deque, defaultdict
  
  N = int(input())
  G = [[] for _ in range(N)]
  
  for i in range(N - 1):
      a, b = map(int, input().split())
      G[a - 1].append(b - 1)
      G[b - 1].append(a - 1)
  
  
  def bfs(s):
      seen = [0] * N
      d = [0] * N
      prev = [0] * N
      todo = deque()
      seen[s] = 1
      todo.append(s)
      while len(todo):
          a = todo.popleft()
          for b in G[a]:
              if seen[b] == 0:
                  seen[b] = 1
                  todo.append(b)
                  d[b] += d[a] + 1
                  prev[b] = a
      return d, prev
  
  
  M = int(input())
  path_list = [0] * M
  for i in range(M):
      u, v = map(int, input().split())
      u -= 1
      v -= 1
      d, prev = bfs(u)
      path = [v]
      for j in range(d[v]):
          prev_v = prev[v]
          path.append(prev_v)
          v = prev_v
      path_list[i] = path
  
  count = defaultdict(int)
  for path in path_list:
      for i in range(len(path) - 1):
          a, b = path[i], path[i + 1]
          a, b = sorted((a, b))
          count[(a, b)] += 1
  
  print(count)
  
problem_description: Statement
  
  We have a tree with N vertices numbered 1 to N. The i-th edge in this tree
  connects Vertex a_i and Vertex b_i.  
  Consider painting each of these edges white or black. There are 2^{N-1} such
  ways to paint the edges. Among them, how many satisfy all of the following M
  restrictions?
  
    * The i-th (1 \leq i \leq M) restriction is represented by two integers u_i and v_i, which mean that the path connecting Vertex u_i and Vertex v_i must contain at least one edge painted black.
samples: [{"input": "3\n    1 2\n    2 3\n    1\n    1 3", "output": "3\n    \n\nThe tree in this input is shown below:  \n  \n![Figure](https://img.atcoder.jp/ghi/5b0208ab1e3bb39a5d4fb7bafbfc448e.png)  \n  \nAll of the M restrictions will be satisfied if Edge 1 and 2 are respectively\npainted (white, black), (black, white), or (black, black), so the answer is 3.\n\n* * *"}, {"input": "2\n    1 2\n    1\n    1 2", "output": "1\n    \n\nThe tree in this input is shown below:  \n  \n![Figure](https://img.atcoder.jp/ghi/d08b3f53dfa4857fe9ffe13fa5d7ae69.png)  \n  \nAll of the M restrictions will be satisfied only if Edge 1 is painted black,\nso the answer is 1.\n\n* * *"}, {"input": "5\n    1 2\n    3 2\n    3 4\n    5 3\n    3\n    1 3\n    2 4\n    2 5", "output": "9\n    \n\nThe tree in this input is shown below:  \n  \n![Figure](https://img.atcoder.jp/ghi/386502bb3c85e0bb5aee64e4e7c087a1.png)  \n  \n\n* * *"}, {"input": "8\n    1 2\n    2 3\n    4 3\n    2 5\n    6 3\n    6 7\n    8 6\n    5\n    2 7\n    3 5\n    1 6\n    2 8\n    7 8", "output": "62\n    \n\nThe tree in this input is shown below:  \n  \n![Figure](https://img.atcoder.jp/ghi/955fa8fd8af658abb24ff2f68b9997be.png)"}]