#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (ll i = 0; i < (n); i++)
const ll INF = 1e18;

int main() {
    ll n, k;
    cin >> n >> k;

    if (n < 2*k - 1) {
        cout << "Impossible" << endl;
        return 0;
    }

    vector<ll> A(n);
    rep(i, n) cin >> A[i];
    vector<ll> dp1(k+1, -INF), dp2(k+1, -INF);
    dp1[0] = 0;
    dp2[0] = 0;
    rep(i, n) {
        vector<ll> ndp1(k+1, -INF), ndp2(k+1, -INF);
        rep(j, k+1) {
            if (j+1 <= k) ndp1[j+1] = max(ndp1[j+1], dp2[j] + A[i]);
            ndp2[j] = max({ndp2[j], dp1[j], dp2[j]});
            ndp1[j] = max(ndp1[j], dp1[j]);
        }
        swap(dp1, ndp1);
        swap(dp2, ndp2);
    }
    cout << max(dp1[k], dp2[k]) << endl;
    return 0;
}