from collections import deque

MIN_INT = -float("inf")


def main():
    N, K = map(int, input().split())
    A = map(int, input().split())

    dp = [[MIN_INT] * (K + 1) for _ in range(2)]
    dp[0][0] = 0
    for a in A:
       new_dp = [[MIN_INT] * (K + 1) for _ in range(2)]

       # 前に拾っていない
       for k in range(K + 1):
           new_dp[0][k] = max(new_dp[0][k], dp[0][k])
           if k + 1 <= K:
               new_dp[1][k+ 1] = max(new_dp[1][k + 1], dp[0][k] + a)

        # 前に拾った
       for k in range(K + 1):
           new_dp[0][k] = max(new_dp[0][k], dp[1][k])
       dp = new_dp 

    answer = MIN_INT
    for j in range(2):
        answer = max(answer, dp[j][K])

    if answer == MIN_INT:
        print("Impossible")
    else:
        print(answer)



if __name__ == "__main__":
    main()
#    main2()