#include <fstream>

using namespace std;

ifstream in("podm.in");
ofstream out("podm.out");

const int Max = 507;
int n, v[Max];
long long d[Max][Max];

int main()
{
    in >> n;
    for(int i = 0; i <= n; ++i)
        in >> v[i];

    for(int i = 1; i < n; ++i)
    {
        for(int j = i + 1; j <= n; ++j)
        {
            long long a = 1LL << 60;
            int D = v[j - i - 1] * v[j];
            for(int z = j - i; z < j; ++z)
            {
                a = min(a, d[j - i][z] + d[z + 1][j] + 1LL * D * v[z]);
            }
            d[j - i][j] = a;
        }
    }
    out << d[1][n] << "\n";

    return 0;
}