题解 | #【模板】链表#

n = int(input())
l = []
for _ in range(n):
    a = input().split()
    if a[0] == 'insert':
        x = int(a[1])
        y = int(a[2])
        if x in l:
            l.insert(l.index(x),y)
        else:
            l.append(y)
    if a[0] == 'delete':
        x = int(a[1])
        if x in l:
            l.remove(x)
if len(l) == 0:
    print('NULL')
else:
    for i in l:
        print(i, end= ' ')