def chmax(DP,i,v):
    if DP[i] < v: DP[i] = v
def chmin(DP,i,v):
    if DP[i] > v: DP[i] = v

def main():

    INF = 1e18
    N, K = map(int, input().split())

    if K > (N + 1)//2:
        exit(print('Impossible'))

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

    dp = [[-INF] * (2) for _ in range(K + 1)]
    dp[0][1] = 0

    for i in range(N):
        ndp = [[-INF] * (2) for _ in range(K + 1)]
        a = A[i]
        for j in range(K + 1):
            for k in range(2):
                if dp[j][k] == -INF:
                    continue

                # 不採用（削除しない）
                # dp[i + 1][j][k|1]
                chmax(ndp[j], k|1, dp[j][k])
                # 採用（削除）
                # dp[i + 1][j + 1][0]
                if k == 1 and j + 1 <= K:
                    chmax(ndp[j + 1], 0, dp[j][k] + a)
        dp = ndp

    ans = max(dp[-1])
    print(ans)

if __name__ == "__main__":
    main()