#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
using i128=__int128;
using P=pair<ll,ll>;
template<typename T> using vc=vector<T>;
template<typename T> using vv=vc<vc<T>>;
using vl=vc<ll>;
using vvl=vc<vc<ll>>;
using vul=vc<ull>;
using vs=vc<string>;
using vb=vc<bool>;
#define rep(i,s,n) for(ll i=s;i<(n);i++)
#define Rep(i,s,n) for(ll i=n;i>=s;i--)
#define nall(x) x.begin(),x.end()
#define rall(a) a.rbegin(),a.rend()
#define pb push_back
#define eb emplace_back
#define pob pop_back
#define nexp(v) next_permutation(v)
#define prep(v) prev_permutation(v)
#define YES cout<<"Yes"<<endl
#define NO cout<<"No"<<endl
#define YN {cout<<"Yes"<<endl;}else{cout<<"No"<<endl;}
#define M1 cout<<"-1"<<endl
const long long INF=(1LL<<62)-(1LL<<31)-1;
#define endl '\n'
using mint=modint998244353;
using mint7=modint1000000007;
//vl dx={1,-1,0,0};vl dy={0,0,1,-1};
//vl dx={0,0,1,1,1,-1,-1,-1};vl dy={1,-1,0,1,-1,0,1,-1};
bool out_grid(ll i, ll j, ll h, ll w){return (!(0<=i && i<h && 0<=j && j<w));}
void chmin(ll &a,ll b){if(a>b)a=b;}
void chmax(ll &a,ll b){if(a<b)a=b;}
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}
ll ceil_div(ll a,ll b){return (a+(b-1))/b;}



int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	ll n,k;
	cin >> n >> k;
	if(k*2>n+1){
		cout << "Impossible" << endl;
		return 0;
	}
	vl a(n);
	rep(i,0,n)cin >> a[i];
	vv<vl> dp(n+1,vvl(k+1,vl(2,-INF)));
	dp[0][0][0]=0;
	rep(i,0,n){
		rep(j,0,k+1){
			if(max(dp[i][j][0],dp[i][j][1])!=-INF)dp[i+1][j][0]=max(dp[i][j][0],dp[i][j][1]);
			if(j<k && dp[i][j][0]!=-INF)dp[i+1][j+1][1]=dp[i][j][0]+a[i];
		}
	}
	cout << max(dp[n][k][0],dp[n][k][1]) << endl;
}