n, k = map(int, input().split())
P = list(map(int, input().split()))
P.sort()
import bisect
ans = 0
for b in range(0, 402):
    i = bisect.bisect_left(P, b)
    if n-i > k:
        continue
    else:
        ans = max(ans, n-i)
print(ans)