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 itertools import combinations
  
  n = int(input())
  ab = [list(map(int, input().split())) for _ in range(n - 1)]
  m = int(input())
  uv = [list(map(int, input().split())) for _ in range(m)]
  
  adj = [[] for _ in range(n)]
  ids = [[-1] * n for _ in range(n)]
  for i, (a, b) in enumerate(ab):
      a -= 1
      b -= 1
      adj[a].append(b)
      adj[b].append(a)
      ids[a][b] = i
      ids[b][a] = i
  
  
  def dfs(s, g):
      d = [-1] * n
      d[s] = 0
      p = [-1] * n
      stack = [s]
  
      while stack:
          u = stack.pop()
          for v in adj[u]:
              if d[v] == -1:
                  d[v] = d[u] + 1
                  p[v] = u
                  stack.append(v)
  
      v = g
      ret = 0
      while v != s:
          i = ids[v][p[v]]
          ret += 1 << i
          v = p[v]
  
      return ret
  
  
  def bin_count(tpl):
      sm_or = 0
      for e in tpl:
          sm_or |= e
  
      return bin(sm_or).count("1")
  
  
  path = [dfs(u - 1, v - 1) for u, v in uv]
  ex = 0
  for i in range(1, m + 1):
      for tpl in combinations(path, i):
          ex += pow(2, n - 1 - bin_count(tpl)) * (-1) ** (i % 2 + 1)
  
  ans = pow(2, n - 1) - ex
  print(ans)
  
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)"}]