#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vl vector<ll>
#define vvl vector<vl>
template<class T> inline int chmax(T &a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline int chmin(T &a, T b) { if (a > b) { a = b; return 1; } return 0; }
auto _ = []() { ios::sync_with_stdio(false); cin.tie(nullptr); return 0; }();
ll INF = 1e18;

int main() {
  
  ll N, K; cin >> N >> K;
  
  if (K > (N + 1) / 2) {
    
    cout << "Impossible" << "\n";
    
    return 0;
    
  }
  
  vl A(N);
  
  for (auto& x : A) cin >> x;
  
  vl dp0(K + 1, -INF);
  vl dp1(K + 1, -INF);
  
  dp0[0] = 0;
  
  for (int i = 0; i < N; i++) {
    
    for (int j = K; j >= 0; j--) {
      
      ll p_dp0 = dp0[j];
      
      if (dp0[j] != -INF || dp1[j] != -INF) dp0[j] = max(dp0[j], dp1[j]);
      
      if (j > 0 && dp0[j - 1] != -INF) chmax(dp1[j], dp0[j - 1] + A[i]);
      
      else dp1[j] = -INF;
      
    }
    
  }
  
  ll ans = max(dp0[K], dp1[K]);
  
  cout << ans << "\n";
  
  return 0;
  
}