Example

Input

5 3
4
2
5


Output

5
2
4
1
3
n, m = map(int, input().split())
e = [int(input()) for _ in range(m)]

used = [False] * (n + 1)

for temp in e[::-1]:
    if not used[temp]:
        used[temp] = True
        print(temp)

for i in range(1, n + 1):
    if not used[i]:
        print(i)


