from collections import deque
from itertools import accumulate
inf = 10**18


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[j,i]: i桁目までみた、j個かたまりできた-> max
dp = [[-inf]*(N+1) for _ in range(K+1)]
dp[0][0] = 0
for i in range(K):
    val = tuple(dp[i][j] - S[j] for j in range(N))
    for j, x in enumerate(sliding_max(val, M), 1):
        dp[i+1][j] = max(dp[i+1][j], x + S[j])

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

print(dp[K][N])