题解 | #数据分类处理#

I = input()
I = I.split()
R = input()
R = R.split()
I.remove(I[0])
R_len = int(R[0])
R.remove(R[0])
R = list(set(R))

for i in range(len(R)):
    R[i] = int(R[i])
R.sort()
for i in range(len(R)):
    R[i] = str(R[i])

s = []
ss = []
index = 0


for i in R:
    index = 0
    for j in range(len(I)):
        if i in I[j]:
            index += 1
    if index == 0:
        continue
    s.append(i)
    ss.append(str(index))
    for j in range(len(I)):
        if i in I[j]:
            s.append(str(j))
            ss.append(I[j])
            
        
merged_list = [item for pair in zip(s, ss) for item in pair]
merged_list.insert(0,str(len(merged_list)))

print(" ".join(merged_list))