INF = 1<<60

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

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

print(dp[-1][-1] if dp[-1][-1] != -INF else "Impossible")