INF = (1 << 61) - 1

N, B, C = map(int, input().split())
A = list(map(int, input().split()))

all_sum = sum(A)

size = 1
while size < N + 1:
    size <<= 1

seg = [INF] * (2 * size)


def set_val(p, x):
    p += size
    seg[p] = x
    while p > 1:
        p >>= 1
        seg[p] = min(seg[p << 1], seg[p << 1 | 1])


def prod(l, r):
    res = INF
    l += size
    r += size

    while l < r:
        if l & 1:
            res = min(res, seg[l])
            l += 1
        if r & 1:
            r -= 1
            res = min(res, seg[r])
        l >>= 1
        r >>= 1

    return res


set_val(0, 0)

for i in range(1, N + 1):
    l = max(0, i - C)
    r = i - (1 if B == 2 and i >= 2 else 0)

    set_val(i, prod(l, r) + A[i - 1])

ans = all_sum - prod(max(0, N + 1 - C), N + 1)

print(ans)