N,K = list(map(int,input().split()))
A = list(map(int,input().split())) + [0]
SUM = sum(A)

INF = 10**18
dp = [[INF for _ in range(K+1)] for _ in range(N+2)]
dp[0][0] = 0

for i in range(N+1):
    for j in range(K+1):
        # 消す
        if(i+2 <= N+1 and j+1 <= K):dp[i+2][j+1] = min(dp[i+2][j+1], dp[i][j] + A[i+1])
        # 消さない
        dp[i+1][j] = min(dp[i+1][j], dp[i][j] + A[i])

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