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

if K > (N+1) // 2:
    print("Impossible")
    exit(0)
    
dp = [[-10**18, -10**18] for _ in range(K+1)]
dp[0][0] = 0

for i in range(N):
    ep = [[-10**18, -10**18] for _ in range(K+1)]
    for j in range(K+1):
        ep[j][0] = max(dp[j][0], dp[j][1])
        if j < K:
            ep[j+1][1] = dp[j][0] + A[i]
    dp = ep

print(max(dp[K]))