N, K = map(int, input().split())
A = list(map(int, input().split()))

from collections import Counter

c = Counter(A)

v = sorted(c.values(), reverse=True)

ans = 0
s = 0
for i in range(len(v)):
    ans += 1
    s += v[i]
    if s >= K:
        break
print(ans)