N,K=map(int, input().split())
cards=list(map(int, input().split()))
counts = [0]*(N + 1)
for i in range(N):
    counts[cards[i]]+=1
counts.sort(reverse=True)
total=0
num_types=0
for count in counts:
    if total>=K:
        break
    total += count
    num_types+=1
print(num_types)