from collections import deque

def Slide_Min(lst,width):
    queue=deque([])
    for i,x in enumerate(lst[:width-1]):
        while queue and x<=lst[queue[-1]]:
            queue.pop()
        queue.append(i)
    slide_min=[]
    for i,x in enumerate(lst[width-1:],width-1):
        while queue and x<=lst[queue[-1]]:
            queue.pop()
        queue.append(i)
        slide_min.append(lst[queue[0]])
        if queue[0]==i-width+1:
            queue.popleft()
    return slide_min

N,K,M=map(int,input().split())
A=[0]+list(map(int,input().split()))
for i in range(1,N+1):
    A[i]+=A[i-1]
inf=1<<60
dp=[-inf]*(N+1)
dp[0]=0
for k in range(1,K+1):
    prev=dp
    dp=[-inf]*(N+1)
    for i,x in enumerate(Slide_Min([inf]*M+[-A[i]-prev[i] for i in range(N)],M)):
        dp[i]=max(dp[i],-A[i]-x)
    for i,x in enumerate(Slide_Min([inf]*M+[A[i]-prev[i] for i in range(N)],M)):
        dp[i]=max(dp[i],A[i]-x)
    ans=dp[N]
print(ans)