#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int n;
  cin >> n;
  vector<int> a(n);
  rep(i, n) cin >> a[i];
  ll ans = 0;
  vector<ll> cnt(501, 0);
  vector<ll> coef(501, 0);
  rep(i, n) {
    for (int j = 1; j <= 500; ++j) coef[j] += cnt[j];
    for (int j = 1; j <= 500; ++j) ans += coef[j] * abs(a[i] - j);
    cnt[a[i]]++;
  }
  cout << ans * 2 << endl;
  return 0;
}