import sys
input = sys.stdin.readline

N, K = map(int, input().split())
A = list(map(int, input().split()))
cnt = [0]*(N+1)
for x in A:
    cnt[x] += 1
cnt.sort(reverse=True)
ans = 0
for x in cnt:
    K -= x
    ans += 1
    if K <= 0:
        break
print(ans)