import sys, time, random, heapq, math, itertools, copy
from collections import deque, Counter, defaultdict
#from sortedcontainers import SortedSet, SortedList
from bisect import bisect, bisect_left, bisect_right
import heapq as hq
from functools import cache, cmp_to_key
def debug(*x):print('debug:',*x, file=sys.stderr)
sys.setrecursionlimit(300000)
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 61 - 1
mod = 998244353
dir = [(0, 1), (0, -1), (1, 0), (-1, 0)]

N, K = mi()
A = li()
if N < 2 * K - 1:
    print("Impossible")
    exit()
dp = [[-inf, -inf] for _ in range(K+1)]
dp[0][0] = 0
for i in range(N):
    next_dp = [[-inf, -inf] for _ in range(K+1)]
    for j in range(K+1):
        if j + 1 < K+1 and dp[j][0] != -inf:
            # 選ぶ
            next_dp[j+1][1] = max(next_dp[j+1][1], dp[j][0] + A[i])
        #選ばない
        next_dp[j][0] = max(next_dp[j][0], dp[j][0], dp[j][1])
    dp = next_dp

debug(dp)

ans = max(dp[-1][0], dp[-1][1])

print(ans)