n, k = map(int , input().split(" "))
films = [x for x in range(n + 1)]
filmInDVD = 0
filmseq = input().split(" ")
for f in [int(j) for j in filmseq]:
    if f != filmInDVD:
        if filmInDVD != 0:
            films[filmInDVD] = films[f]
            films[f] = 0
            filmInDVD = f
        else:
            films[f] = 0
            films[0] = f
            filmInDVD = f
s = {k: f if f > 0 else -1 for f, k in enumerate(films)}
for i in range(1, n + 1):
    print(s[i], end=" ")