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


if N // 2 + N % 2 < K:
    exit(print("Impossible"))

INF = 10**20

dp = [[-INF] * 2 for _ in range(K + 1)]

PASSED = 0
BANNED = 1

dp[0][PASSED] = 0

for submit_idx in range(N):
    ndp = [[-INF] * 2 for _ in range(K + 1)]
    for ban_cnt in range(K):
        for prv in (PASSED, BANNED):

            # pass
            ndp[ban_cnt][PASSED] = max(ndp[ban_cnt][PASSED], dp[ban_cnt][prv])

            if prv == PASSED:
                # ban
                ndp[ban_cnt + 1][BANNED] = max(
                    ndp[ban_cnt + 1][BANNED], dp[ban_cnt][prv] + A[submit_idx]
                )
    dp, ndp = ndp, dp
    # print(dp)
print(max(dp[K]))