#include <fstream>

using namespace std;

const long long INF = 1LL << 62,
                NMAX = 501;

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

int n;
short D[NMAX];
long long M[NMAX - 1][NMAX - 1];

void calcul()
{
    for(int d = 1; d < n; ++d)
        for(int i = n - d - 1; i >= 0; --i)
        {
            int j = i + d;
            M[i][j] = INF;
            long long prod = D[i] * D[j + 1];
            for(int k = i; k < j; ++k)
            {
                long long t = M[i][k] + M[k + 1][j] + prod * D[k + 1];
                M[i][j] = min(M[i][j], t);
            }
        }
}

int main()
{
    fin >> n;
    for(int i = 0; i <= n; ++i)
        fin >> D[i];
    calcul();
    fout << M[0][n - 1];
    return 0;
}