import sys
import math

# 入力高速化
#input = sys.stdin.readline
# 再帰回数上限
sys.setrecursionlimit(10**9)

# よくあるmod
#MOD = 1000000007
MOD = 998244353

def is_inside(y, x, h, w):
  return (0 <= y < h and 0 <= x < w)

def solve():
    N, K = map(int, input().split(' '))
    A = list(map(int, input().split(' ')))
    if K > (N+1) // 2:
        print("Impossible")
        return
    dp = [[-10**18] * (K+1) for _ in range(N+1)]
    dp[0][0] = 0
    for i in range(N):
        dp[i+1][0] = dp[i][0]
        if i == 0:
            dp[i+1][1] = A[i]
        for k in range(K):
            dp[i+1][k+1] = max(dp[i][k+1], dp[i+1][k+1])
            if i >= 1:
                dp[i+1][k+1] = max(dp[i+1][k+1], dp[i-1][k] + A[i])

    ans = -1
    for i in range(N+1):
        ans = max(ans, dp[i][K])
    print(ans)
if __name__ == '__main__':
    T = 1
    for _ in range(T):
        solve()