1)큰 수의 법칙

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

cnt=0
res=0
first=max(a)
a.remove(first)
second=max(a)

while True:
  if cnt==M:
    break

  for _ in range(K):
    res+=first
    cnt+=1
  
  res+=second
  cnt+=1

print(res)