#include <vector>
#include <algorithm>
#include <iostream>
#include <set>
#include <cmath>
#include <map>
#include <random>
#include <cassert>
#include <ctime>
#include <cstdlib>
#include <queue>
#include <limits.h>
using namespace std;
int main () {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, k;
cin >> n >> k;
int64_t arr[n]; int64_t pref[n + 1]; pref[0] = 0;
for (int i = 0; i < n; i++) {
cin >> arr[i];
pref[i + 1] = pref[i] + arr[i];
}
if (k == 0) {
cout << 0;
return 0;
}
int64_t dp[n - 1][k + 1];
for (int i = 0; i < n - 1; i++) {
//[0 ... i] [i + 1 ... n - 1]
dp[i][1] = (pref[i + 1]) * (pref[n] - pref[i + 1]);
}
for (int j = 2; j <= k; j++) {
for (int i = 0; i < n - 1; i++) {
dp[i][j] = 0;
for (int prev = 0; prev < i; prev++) {
dp[i][j] = max(dp[i][j], dp[prev][j - 1] + (pref[i + 1] - pref[prev + 1]) * (pref[n] - pref[i + 1]));
}
}
}
int64_t myMax = 0;
for (int i = 0; i < n; i++) {
//cout << dp[i][k] << '\n';
myMax = max(myMax, dp[i][k]);
}
cout << myMax << '\n';
}
