N, K = map(int, input().split())
A = list(map(int, input().split()))
if N < 2 * (K - 1) + 1:
    print('Impossible')
    exit()

INF = 10**20
dp = [[[-INF]*2 for _ in range(K + 1)] for _ in range(N + 1)]
dp[0][0][0] = 0
for i in range(N):
    for j in range(K + 1):
        if dp[i][j][0] != -INF:
            dp[i+1][j][0] = max(dp[i+1][j][0], dp[i][j][0])
            if j+1 <= K:
                dp[i+1][j+1][1] = max(dp[i+1][j+1][1], dp[i][j][0] + A[i])
        if dp[i][j][1] != INF:
            dp[i+1][j][0] = max(dp[i+1][j][0], dp[i][j][1])
print(max(dp[-1][-1]))