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

dp = [[-10 ** 18] * (K + 1) for i in range(N + 2)]
dp[-1][0] = dp[0][0] = 0
for i in range(N):
	dp[i + 1] = dp[i].copy()
	for k in range(K):
		dp[i + 1][k + 1] = max(dp[i + 1][k + 1], dp[i - 1][k] + A[i])

print(dp[N][K] if dp[N][K] > -1e15 else "Impossible")