#include <bits/stdc++.h>
using namespace std;
const int MAXN = 4005;
const long long INF = 1ll << 60;
int n, m, a[MAXN];
long long f[MAXN][MAXN];
int Dfs(int l, int r) {
  if (l > r) return 0;
  if (l == r) {
    f[l][0] = 0;
    f[l][1] = (m - 1ll) * a[l];
    return l;
  }
  int w = l;
  for (int i = l + 1; i <= r; i++)
    if (a[i] < a[w]) w = i;
  long long *f1 = f[Dfs(l, w - 1)], *f2 = f[Dfs(w + 1, r)];
  for (int i = 1; i <= r - l + 1; i++) f[w][i] = -INF;
  int l1 = w - l, l2 = r - w;
  for (int i = 0; i <= l1; i++)
    for (int j = 0; j <= l2; j++)
      f[w][i + j] = max(f[w][i + j], f1[i] + f2[j] - 2ll * i * j * a[w]);
  for (int i = r - l + 1; i; i--)
    f[w][i] = max(f[w][i], f[w][i - 1] + a[w] * (m + 1ll - i * 2));
  return w;
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++) scanf("%d", a + i);
  printf("%lld\n", f[Dfs(1, n)][m]);
  return 0;
}
