//WA
#include <iostream>
#include <algorithm>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
//#define endl "\n";
const long long INF = 1e9;
int main(){
    ll N, K;
    cin >> N >> K;
    vector<ll> A(N);
    for(int i = 0; i < N; i++) cin >> A[i];
    
    //N/2<Kならむり
    if((N + 1)/2 < K){
        cout << "Impossible" << endl;
        return 0;
    }
    
    vector<vector<ll>> dp(K + 1, vector<ll>(2, -INF));
    dp[0][0] = 0;
    for(int i = 0; i < N; i++){
        vector<vector<ll>> tmp(K + 1, vector<ll>(2, -INF));
        
        for(int j = 0; j <= K; j++){
            //選ぶ
            if(j + 1 <= K) tmp[j + 1][1] = max(tmp[j + 1][1], dp[j][0] + A[i]);
            //選ばない
            tmp[j][0] = max(tmp[j][0], dp[j][0]);
            tmp[j][0] = max(tmp[j][0], dp[j][1]);
        }
        swap(dp, tmp);
    }
    ll ans = max(dp[K][0], dp[K][1]);
    cout << ans << endl;
    return 0;
}