大数の法則[グリディ]

n,m,k=map(int,input().split())

data=list(map(int,input().split()))
data.sort()
first=data[n-1]
second=data[n-2]
answer=0

while True:
    for _ in range(k):
        if m==0:
            break
        answer+=first
        m-=1
    if m==0:
        break
    answer+=second
    m-=1
  

print(answer)