#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main()
{
  int n, k;
  cin >> n >> k;
  if ((n + 1) / 2 < k)
  {
    cout << "Impossible" << endl;
    return 0;
  }
  vector<int> a(n);
  for (int i = 0; i < n; ++i) cin >> a[i];
  vector<vector<long long>> dp(n + 1, vector<long long> (k + 1, -1e18));
  dp[0][0] = 0;
  for (int i = 0; i < n; ++i)
  {
    for (int j = 0; j <= k; ++j) dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);
    for (int j = 0; j < k; ++j)
    {
      int to = min(i + 2, n);
      dp[to][j + 1] = max(dp[to][j + 1], dp[i][j] + a[i]);
    }
  }
  cout << dp[n][k] << endl;
}