xd

#include <bits/stdc++.h>

using namespace std;

vector<int> a;
map<pair<int, int>, int> m;


int rec(int l, int r){
    if(m.count({l, r})){
        return m[{l, r}];
    }
    if(r - l <= 1){
        return 0;
    }
    int ans = 1e9;
    for(int i = l + 1; i < r; ++i){
        int sum = rec(l, i) + rec(i, r) + a[i] * (a[l] + a[r]);
        ans = min(ans, sum);
    }
    m[{l, r}] = ans;
    return ans;
}

int main() {
    ios_base::sync_with_stdio;
    cin.tie(0);
    cout.tie(0);
    int n;
    cin >> n;
    a.resize(n);
    for(int i = 0; i < n; ++i){
        cin >> a[i];
    }
    cout << rec(0, n - 1);

}