from collections import defaultdict

a = defaultdict(int)
n, k = map(int, input().split())
for i in list(map(int, input().split())):
    a[i] += 1
b = sorted(list(a.values()))
m = len(b)
ans = 0
while k > 0:
    ans += 1
    k -= b[m - ans]
print(ans)