Buggy python submission (verdict: Time Limit Exceeded):
import sys
from collections import defaultdict
readline = sys.stdin.readline
N, = map(int, readline().split())
def con(ll,E):
    rs = []
    for u, v in zip(ll,ll[1:]):
        u, v = sorted([u,v])
        rs.append(E[(u,v)])
    return set(rs)

def process():
    G = [[] for _ in range(N+1)]
    E = dict()
    for i in range(N-1):
        a, b = sorted(map(int, readline().split()))
        G[a].append(b)
        G[b].append(a)
        E[(a,b)] = i

    M, = map(int, readline().split())
    qes = dict()
    for _ in range(M):
        u, v = sorted(map(int, readline().split()))
        if u not in qes:
            qes[u] = list()
        qes[u].append(v)
    dep = []
    for i in qes:
        ms = qes[i]
        path = []
        stack = [i]
        vs = set([i])
        while stack:
            v = stack.pop()
            if v > 0:
                vs.add(v)
#                parent = path[-1]
                path.append(v)
                for u in G[v]:
                    if u in vs:
                        continue
                    if u in ms:
                        dep.append(con(path+[u],E))
                    stack += [-v, u]
            else:
                path.pop()
    r = 0
    for i in range(1,2**M):
        t = 0
        ns = set()
#        lns = 
        for j in range(M):
            if i % 2:
                ns = ns | dep[j]
                t += 1
            i = i>>1
        xx = (1 if t%2 else -1)*2**(N-1-len(ns))
        r += xx
    print(2**(N-1)-r)
if __name__ == '__main__':
    process()


Fixed submission:
import sys
from collections import defaultdict
readline = sys.stdin.readline
N, = map(int, readline().split())
def con(ll,E):
    r = 0
    for u, v in zip(ll,ll[1:]):
        u, v = sorted([u,v])
        r += 1<<E[(u,v)]
    return r

def process():
    G = [[] for _ in range(N+1)]
    E = dict()
    for i in range(N-1):
        a, b = sorted(map(int, readline().split()))
        G[a].append(b)
        G[b].append(a)
        E[(a,b)] = i

    M, = map(int, readline().split())
    qes = dict()
    for _ in range(M):
        u, v = sorted(map(int, readline().split()))
        if u not in qes:
            qes[u] = list()
        qes[u].append(v)
    dep = []
    for i in qes:
        ms = qes[i]
        path = []
        stack = [i]
        vs = set([i])
        while stack:
            v = stack.pop()
            if v > 0:
                vs.add(v)
#                parent = path[-1]
                path.append(v)
                for u in G[v]:
                    if u in vs:
                        continue
                    if u in ms:
                        dep.append(con(path+[u],E))
                    stack += [-v, u]
            else:
                path.pop()
    r = 0
    for i in range(1,2**M):
        t = 0
        ns = 0
#        lns = 
        for j in range(M):
            if i % 2:
                ns = ns | dep[j]
                t += 1
            i = i>>1
        xx = (1 if t%2 else -1)*2**(N-1-bin(ns).count("1"))
        r += xx
    print(2**(N-1)-r)
if __name__ == '__main__':
    process()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from collections import defaultdict
readline = sys.stdin.readline
N, = map(int, readline().split())
def con(ll):
    rs = []
    for u, v in zip(ll,ll[1:]):
        u, v = sorted([u,v])
        rs.append(100*u+v)
    return set(rs)

def process():
    G = [[] for _ in range(N+1)]
    for v in range(N-1):
        a, b = map(int, readline().split())
        G[a].append(b)
        G[b].append(a)
    M, = map(int, readline().split())
    qs = set()
    ss = set()
    for _ in range(M):
        u, v = sorted(map(int, readline().split()))
        qs.add((u,v))
        ss.add(u)
    dep = dict()
    for i in ss:
        path = []
        stack = [i]
        vs = set([i])
        while stack:
            v = stack.pop()
            if v > 0:
                vs.add(v)
#                parent = path[-1]
                path.append(v)
                for u in G[v]:
                    if u in vs:
                        continue
                    if (i,u) in qs:
                        dep[(i,u)] = con(path+[u])
                    stack += [-v, u]
            else:
                path.pop()
    qs = list(qs)
    r = 0
    for i in range(1,2**M):
        t = 0
        ns = set()
        for j in range(M):
            if i % 2:
                ns = ns | dep[qs[j]]
                t += 1
            i = i>>1
        xx = (1 if t%2 else -1)*2**(N-1-len(ns))
        r += xx
    print(2**(N-1)-r)
if __name__ == '__main__':
    process()


Fixed submission:
import sys
from collections import defaultdict
readline = sys.stdin.readline
N, = map(int, readline().split())
def con(ll,E):
    r = 0
    for u, v in zip(ll,ll[1:]):
        u, v = sorted([u,v])
        r += 1<<E[(u,v)]
    return r

def process():
    G = [[] for _ in range(N+1)]
    E = dict()
    for i in range(N-1):
        a, b = sorted(map(int, readline().split()))
        G[a].append(b)
        G[b].append(a)
        E[(a,b)] = i

    M, = map(int, readline().split())
    qes = dict()
    for _ in range(M):
        u, v = sorted(map(int, readline().split()))
        if u not in qes:
            qes[u] = list()
        qes[u].append(v)
    dep = []
    for i in qes:
        ms = qes[i]
        path = []
        stack = [i]
        vs = set([i])
        while stack:
            v = stack.pop()
            if v > 0:
                vs.add(v)
#                parent = path[-1]
                path.append(v)
                for u in G[v]:
                    if u in vs:
                        continue
                    if u in ms:
                        dep.append(con(path+[u],E))
                    stack += [-v, u]
            else:
                path.pop()
    r = 0
    for i in range(1,2**M):
        t = 0
        ns = 0
#        lns = 
        for j in range(M):
            if i % 2:
                ns = ns | dep[j]
                t += 1
            i = i>>1
        xx = (1 if t%2 else -1)*2**(N-1-bin(ns).count("1"))
        r += xx
    print(2**(N-1)-r)
if __name__ == '__main__':
    process()