题解 | #数据分类处理#

line1 = list(map(str,input().split()))[1:]
line2 = list(map(str,input().split()))[1:]
line2_set = []
line_all = []
for i in line2:    #R去重
    if i in line2_set:
        continue
    else:
        line2_set.append(i)
line2_set.sort(key=int)
for i in line2_set:
    a = []
    n = 0
    line = []
    for j in range(len(line1)):
        if i in line1[j] :
            a.append(line1[j])
            line.extend([str(j),line1[j]])
            n += 1
    if n!=0:
        line_all.extend([i,str(n)])
        line_all.extend(line)
line_all.insert(0,str(len(line_all)))
lst = ' '.join(line_all)
print(lst)