from collections import deque
from itertools import accumulate
inf = 10**15


def sliding_max(A, rng):
    d = deque()
    for i, a in enumerate(A):
        while d and d[0] <= i - rng:
            d.popleft()
        while d and A[d[-1]] < a:
            d.pop()
        d.append(i)
        yield A[d[0]]


N, K, M = map(int, input().split())
A = list(map(int, input().split()))
S = [0] + list(accumulate(A))

dp = [-inf] * (N+1)
dp[0] = 0

for i in range(K):
    newDP = [-1] * (N+1)

    val = tuple(dp[j] - S[j] for j in range(N))
    for j, x in enumerate(sliding_max(val, M), 1):
        newDP[j] = max(newDP[j], x + S[j])

    val = tuple(dp[j] + S[j] for j in range(N))
    for j, x in enumerate(sliding_max(val, M), 1):
        newDP[j] = max(newDP[j], x - S[j])

    dp = newDP

print(dp[N])