all_num = input("請輸入總數")
tree_list = [int(all_num)]
find_list = [None] * (int(all_num)+1)
find_ans_list = [None] * (int(all_num)+1)
high_tmp = 0
root = 0
flag = 0
find = 0
for i in range(int(all_num)):
    tree_list.append(input("請輸入節點"))

for j in range(1,int(all_num)+1):         #陣列
    find_list[j] = j
    for k in range(1,int(all_num)+1):
        x = str(tree_list[k]).split(" ")
        for l in range(1,len(x)):           #陣列值
            if int(x[l]) == j:
                find_ans_list[j] = k
                
for i in range(1,int(all_num)+1):
    if find_ans_list[i] == None:
        root = i
        print(root)
            
#for i in range(1,int(all_num)+1):
 #   if tree_list[i] == 0:
#        while find = root: