from sys import stdin, stdout

meresek = dict()
nemgyakori = list()


s = input()
n,k = (int(x) for x in s.split())
m = 0

lines = stdin.readlines()

for line in lines:
    x = int(line)
    if (x in meresek):
        meresek[x] = meresek[x] + 1
    else:
        meresek[x] = 1

for key in meresek:
    if meresek[key] <= k:
        m = m + 1
        nemgyakori.append(key)

print(m)
nemgyakori.sort()

for key in nemgyakori:
    print(key)