题解 | #数据分类处理#

    while True:
        I = (input().split())[1:]
        R = list(set(map(int, input().split()[1:])))
        R.sort()
        res = []
        for r in R:
            tmp = []
            cnt = 0
            for index,i in enumerate(I):
                if str(r) in i:
                    cnt+=1
                    tmp.extend([str(index),i])
            if cnt != 0:
                tmp.insert(0, str(cnt))
                tmp.insert(0, str(r))
                res.extend(tmp)
        print(str(len(res))+' '+' '.join(res))
except:
    pass