#include <bits/stdc++.h>

using i64 = long long;

constexpr int M = 500;

int main() {
    int n; std::cin >> n;
    i64 res = 0;
    std::vector<i64> cnt(M + 1), sum(M + 1);
    for (int i = 1; i <= n; ++i) {
        int x; std::cin >> x;
        for (int j = 1; j <= M; ++j)
            res += (i * cnt[j] - sum[j]) * std::abs(x - j);
        cnt[x] += 1;
        sum[x] += i;
    }
    std::cout << res * 2 << "\n";
    return 0;
}