//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
#define all(a) (a).begin(), (a).end()
using ll = long long;
const ll INF32 = 2e9;
const ll INF64 = 4e18;

void printYN(bool ok){
    if(ok)cout << "Yes" << endl;
    else cout << "No" << endl;
    return;
}

int main() {
    ll N, K;
    cin >> N >> K;
    vector<ll> A(N+2, 0);
    rep(i, N)cin >> A[i+2];
    vector<vector<ll>> dp(K+1, vector<ll>(N+2, -INF64));
    rep(i, N+2)dp[0][i] = 0;
    for(ll k= 1; k <= K; k++){
        for(ll i = 2; i <N+2;i++){
            dp[k][i] = max(dp[k][i-1], dp[k-1][i-2]+A[i]);
        }
    }
    if(dp[K][N+1]>=-1e16)cout << dp[K][N+1] << endl;
    else cout << "Impossible\n";
    return 0;
}