#include <bitset>
#include<iostream>
// #include<fstream>
#include<vector>
#include<array>
#include<algorithm>
#include<set>
#include<cmath>
#include<unordered_map>
#include<iomanip>
#include <map>
#include <queue>
#include <stack>
#include <cstring>
#include <climits>
#include <chrono>
#include <random>
#include <cassert>
using namespace std;
#define PRINTARRAY(st, en, a) for(int _i = st; _i <= en; _i++) {cout << a[_i] << (_i != en ? " " : "\n");}
#define SZ(A) (int)A.size()
using LL = long long;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const LL INF = 1e18;
void solve() {
int n, k;
cin >> n >> k;
if (n > 2000) {
cout << -1 << "\n";
return;
}
vector<int> A(n + 1, 0);
for(int i = 1; i <= n; i++) {
cin >> A[i];
}
// vector<vector<LL>> dp(k + 1, vector<LL>(n + 1, INF));
vector<vector<LL>> dp(n + 1, vector<LL>(k + 1, -INF));
// vector<vector<LL>> dp2(n + 1, vector<LL>(k + 1, -INF));
vector<LL> dp2(k + 1, -INF);
dp[0][0] = 0;
dp2[0] = 0;
// dp2[0][0] = 0;
// vector<LL> dp (k + 1, INF);
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= min(i, k); j++) {
dp[i][j] = max({dp[i - 1][j] + A[i], dp2[j - 1] + A[i]});
}
for(int j = 1; j <= min(i, k); j++) {
dp2[j] = max(dp2[j], dp[i][j]);
}
// cout << i << "-----" << endl;
// PRINTARRAY(1, k, dp[i]);
// PRINTARRAY(1, k, dp2);
}
cout << *max_element(dp2.begin(), dp2.end()) << "\n";
}
int main() {
cin.tie(0);
ios_base::sync_with_stdio(false);
int testcase = 1;
// cin >> testcase;
while(testcase--) {
solve();
}
}
