n, k, x = list(map(int, input().split()))
from heapq import *
hq = []
ans = 0
Ans = -1<<60
for a in list(map(int, input().split())):
    ans += a-x
    heappush(hq, a)
    if len(hq) > k:
        ans -= heappop(hq)
    Ans = max(Ans, ans)
print(Ans)