#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 y = 1; y < x; ++y)
            res += (i * cnt[y] - sum[y]) * (x - y);
        for (int y = x + 1; y <= M; ++y)
            res += (i * cnt[y] - sum[y]) * (y - x);
        cnt[x] += 1;
        sum[x] += i;
    }
    std::cout << res * 2 << "\n";
    return 0;
}