题解 | #【模板】链表#

n = int(input())
input_nums = []
num_list = []

for i in range(n):
    op, *input_nums = input().split()
    if op == "insert":
        try:
            index = num_list.index(input_nums[0])
            num_list.insert(index, input_nums[1])
        except:
            num_list.append(input_nums[1])

    elif op == "delete":
        try:
            num_list.remove(input_nums[0])
        except:
            pass

if len(num_list):
    print(" ".join(num_list))
else:
    print("NULL")