/* -*- coding: utf-8 -*-
 *
 * 3683.cc:  No.3683 繧ｵ繝ｼ繝舌・莉｣縺後ｂ縺｣縺溘＞縺ｪ縺・ - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 100000;
const int MAX_K = 50;
const long long LINF = 1LL << 60;

/* typedef */

using ll = long long;

/* global variables */

int as[MAX_N];
ll dp[MAX_N + 1][MAX_K + 1];

/* subroutines */

void setmax(ll &a, ll b) { if (a < b) a = b; }

/* main */

int main() {
  int n, k;
  scanf("%d%d", &n, &k);
  for (int i = 0; i < n; i++) scanf("%d", as + i);

  for (int i = 0; i <= n; i++) fill(dp[i], dp[i] + k + 1, -LINF);
  dp[0][0] = 0;

  for (int i = 0; i < n; i++)
    for (int j = 0; j <= k; j++)
      if (dp[i][j] > -LINF) {
	setmax(dp[i + 1][j], dp[i][j]);
	if (j < k)
	  setmax(dp[min(n, i + 2)][j + 1], dp[i][j] + as[i]);
      }

  if (dp[n][k] > -LINF) printf("%lld\n", dp[n][k]);
  else puts("Impossible");
  
  return 0;
}