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: n = int(input())
  ab = {i: [] for i in range(n)}
  for j in range(n - 1):
      a, b = [int(i) - 1 for i in input().split()]
      ab[a].append((b, j))
      ab[b].append((a, j))
  
  
  def dfs(a, b, d=[], c=-1):
      if a == b:
          return d
      for i in ab[a]:
          if i[0] == c:
              continue
          e = dfs(i[0], b, d + [i[1]], a)
          if len(e) != 0:
              return set(e)
      return set()
  
  
  m = int(input())
  ms = []
  for _ in range(m):
      u, p = [int(i) - 1 for i in input().split()]
      ms.append(dfs(u, p))
  
  ans = 0
  for i in range(1 << m):
      k = 0
      a = set()
      for j in range(m):
          if (i >> j) & 1 == 1:
              k += 1
              a |= ms[j]
      if k % 2 == 1:
          ans += 2 ** (n - 1 - len(a))
      elif k != 0:
          ans -= 2 ** (n - 1 - len(a))
  
  print(2 ** (n - 1) - 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)"}]