import sys
def debug(*args):
    print(*args, file=sys.stderr)

N, K = map(int, input().split())
A = list(map(int, input().split()))
INF = 10**18

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

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

if dp[N+1][K] == -INF:
    print("Impossible")
else:
    print(dp[N+1][K])