#include <bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
#pragma GCC target("avx2")
#pragma GCC optimization("O3")
#pragma GCC optimization("unroll-loops")
int n, m;
int a[4007];
int mn[4007][4007];
long long dp[4007][4007];
void f(int l, int r) {
  if (l >= r) {
    return;
  }
  int wh = mn[l][r];
  f(l, wh - 1);
  f(wh + 1, r);
  int tp = 0;
  for (int x = 0; x <= wh - l; ++x) {
    for (int y = 0; y <= r - wh; ++y) {
      long long aux = 0;
      aux += dp[mn[l][wh - 1]][x];
      if (l <= wh - 1) {
        aux += 1LL * (a[mn[l][wh - 1]] - a[mn[l][r]]) * x * (m - x);
      }
      aux += dp[mn[wh + 1][r]][y];
      if (wh + 1 <= r) {
        aux += 1LL * (a[mn[wh + 1][r]] - a[mn[l][r]]) * y * (m - y);
      }
      dp[wh][x + y] = max(dp[wh][x + y], aux);
    }
  }
  for (int i = r - l + 1; i >= 1; --i) {
    dp[wh][i] = max(dp[wh][i], dp[wh][i - 1]);
  }
}
void input() {
  cin >> n >> m;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
  }
  for (int i = 1; i <= n; ++i) {
    mn[i][i] = i;
    for (int j = i + 1; j <= n; ++j) {
      mn[i][j] = mn[i][j - 1];
      if (a[j] < a[mn[i][j]]) {
        mn[i][j] = j;
      }
    }
  }
}
void solve() {
  f(1, n);
  cout << dp[mn[1][n]][m] << "\n";
}
int main() {
  ios_base ::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  t = 1;
  while (t--) {
    input();
    solve();
  }
  return 0;
}
