#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 5e5 + 5, inf = 1e18;
int n, a[N], d[N];
int f[N], g[N];
signed main() {
  cin >> n;
  for (int i = 1; i <= n; ++i) cin >> a[i];
  for (int i = 1; i < n; ++i) d[i] = a[i + 1] - a[i];
  sort(d + 1, d + n);
  memset(f, 0x3f, sizeof f);
  int sum = 0, MX = 0;
  auto checkmin = [] (int &x, int y) {
    x = min(x, y);
  };
  f[0] = 0;
  for (int i = 1; i < n; ++i) {
    sum += d[i];
    for (int j = 0; j <= MX + i * d[i]; ++j) g[j] = inf;
    for (int s = 0; s <= MX; ++s) {
      if (f[s] >= inf) continue;
      checkmin(g[s + sum], f[s] + sum * sum);
      checkmin(g[s + i * d[i]], f[s] + i * d[i] * d[i] + 2 * s * d[i]);
    }
    MX += i * d[i];
    for (int j = 0; j <= MX; ++j)
      f[j] = g[j];
  }
  int ans = inf;
  for (int i = 0; i <= MX; ++i) {
    if (f[i] >= inf) continue;
    f[i] = f[i] * n - i * i;
    ans = min(ans, f[i]);
  }
  cout << ans;
  return 0;
}