그리디_큰 수의 법칙

 

 

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

 

data = map(list(int, input().split()))

 

first = data[n - 1]

second = data[n - 2]

 

result = 0

 

while True:

  for i in range(k):

    if m == 0:

      break

    result += first

    m -= 1

  if m == 0:

    break

  result += second

  m -= 1

print(result)