#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    int n, k;
    cin >> n >> k;
    if ((n + 1) / 2 < k) {
        cout << "Impossible" << endl;
        return 0;
    }
    vector dp(k + 1, vector<ll>(2, -1LL << 60));
    dp[0][0] = 0;
    while (n--) {
        int a;
        cin >> a;
        vector ep(k + 1, vector<ll>(2, -1LL << 60));
        rep(i, k + 1) {
            if (i != k)
                ep[i + 1][1] = max(ep[i + 1][1], dp[i][0] + a);
            ep[i][0] = max(ep[i][0], dp[i][0]);
            ep[i][0] = max(ep[i][0], dp[i][1]);
        }
        dp = ep;
    }
    cout << max(dp.back()[0], dp.back()[1]) << endl;
    return 0;
}