3717

#include <iostream>
#include <vector>
#include <list>
#include <algorithm>
#include <string>
#include <math.h>
#include <climits>

//#include <chrono>
//#include <fstream>
//#include <bits/stdc++.h>

#define mp make_pair
#define pb push_back
#define eb emplace_back
#define x first
#define y second
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define FOR(i,a,b) for (int i = (a); i < (b); i++)
#define RFOR(i,b,a) for (int i = (b) - 1; i >= (a); i--)

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef vector<int> veci;
typedef vector<bool> vecb;
typedef vector<vector<int>> vvi;
typedef vector<vector<bool>> vvb;

const int INF_I = 1e9;
const ll INF_LL = 1e18;

int main() {
    /*ifstream cin("in.txt");
    ofstream cout("out.txt");
    auto start_time = chrono::high_resolution_clock::now();*/

    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n;
    cin >> n;
    veci vec(n);
    for (int i = 0; i < n; i++)
        cin >> vec[i];
    vvi dp(n, veci(n, INT_MAX));
    for (int i = 0; i < n - 2; i++)
        dp[i][i + 2] = vec[i + 1] * (vec[i] + vec[i + 2]);
    for (int i = 0; i < n - 1; i++)
        dp[i][i + 1] = 0;
    for (int i = 0; i < n; i++)
        dp[i][i] = 0;
    for (int len = 3; len < n; len++)
        for (int beg = 0; beg < n - len; beg++)
            for (int k = beg + 1; k < beg + len; k++)
                dp[beg][beg + len] = min(dp[beg][beg + len], dp[beg][k] + dp[k][beg + len] + vec[k] * (vec[beg] + vec[beg + len]));

    cout << dp[0][n - 1] << endl;



    /*auto end_time = chrono::high_resolution_clock::now();
    chrono::duration<double> duration = end_time - start_time;
    cout << duration.count() << "\n";
    cin.close();
    cout.close();*/
    return 0;
}