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())
  g = [[] for _ in range(n)]
  e = []
  for _ in range(n - 1):
      a, b = map(int, input().split())
      a, b = min(a, b), max(a, b)
      g[a - 1].append(b - 1)
      g[b - 1].append(a - 1)
      e.append((a - 1, b - 1))
  m = int(input())
  l = [set() for _ in range(m)]
  for i in range(m):
      u, v = map(int, input().split())
      s = [u - 1]
      dist = [-1] * n
      dist[u - 1] = 0
      r = [-1] * n
      while s:
          d = s.pop()
          for node in g[d]:
              if dist[node] == -1:
                  s.append(node)
                  dist[node] = dist[d] + 1
                  r[node] = d
      d = v - 1
      while r[d] != -1:
          a, b = min(d, r[d]), max(d, r[d])
          l[i].add(e.index((a, b)))
          d = r[d]
  ans = 0
  for i in range(2**m):
      cnt = 0
      s = set()
      for j in range(m):
          if (i >> j) & 1:
              cnt += 1
              s |= l[j]
      if cnt % 2:
          ans -= 2 ** (n - len(s) - 1)
      else:
          ans += 2 ** (n - len(s) - 1)
  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)"}]