#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
template <typename K, typename V>
using umap = unordered_map<K, V>;

#define rep(i, n) for (int i = 0; i < n;i++)
#define rep1(i, n) for (int i = 1; i <= n;i++)
#define rrep(i, n) for (int i = n - 1; i >= 0;i--)
#define rrep1(i, n) for (int i = n; i >= 1;i--)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define INF 1LL << 60
#define chmin(a, b) a = min(a, b)
#define chmax(a, b) a = max(a, b)

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, k;
    cin >> n >> k;


    vector<ll> a(n + 1);
    rep1(i, n) {
        cin >> a[i];
    }

    vector<vector<ll>> dp(n + 1, vector<ll>(k + 1, -INF));
    dp[0][0] = 0;
    rep1(i, n) {
        dp[i][0] = 0;
        rep1(j, k) {
            dp[i][j] = dp[i - 1][j];
            if (i == 1) {
                if (j == 1) {
                    chmax(dp[i][j], a[i]);
                }
            } else if (i >= 2 && dp[i - 2][j - 1] != -INF) {
                chmax(dp[i][j], dp[i - 2][j - 1] + a[i]);
            }
        }
    }
    if (dp[n][k] == -INF) {
        cout << "Impossible" << endl;
        return 0;
    }
    cout << dp[n][k] << endl;
}