N, K = map(int, input().split())
A = list(map(int, input().split()))
D = dict()
for a in A:
    if a not in D:
        D[a]=1
    else:
        D[a]+=1
V = list(D.values())
V.sort()
cnt = 0
while K>0:
    v = V.pop()
    K-=v
    cnt+=1
print(cnt)