#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;


int main(void)
{
    std::ios::sync_with_stdio(false);
    ifstream in("podm.in");
    ofstream out("podm.out");

    vector<vector<int>> m(505, vector<int>(3, 0));
    vector<vector<long>> dp(505, vector<long>(505, 0));

    int n;

    in >> n >> m[1][0];

    for (int i = 1; i <= n; ++i) {
        in >> m[i][1];
        m[i + 1][0] = m[i][1];
    }

    // for (int  i = 1; i <= n; i++) {
    //     cout << m[i][0] << " " << m[i][1]<< endl;
    // }


    for (int j = 1; j <= n; ++j) {
        for (int k = 1; k < n; ++k) {
            for (int i = 1; i <= n - k; ++i) {
                if (i < j) {

                    long a = dp[i][j - 1] + m[i][0] * m[j - 1][1] * m[j][1];
                    long b = dp[i + 1][j] + m[i + 1][0] * m[j][1] * m[i][0];

                    dp[i][j] = min(a, b);
                }
            }
        }
    }

    // for (int i = 0; i <= n; i++) {
    //     for (int j = 0; j <= n; j++) {
    //         cout << dp[i][j] << " ";
    //     }
    //     cout << endl;
    // }

    out << dp[1][n];


    in.close();
    out.close();
    return 0;
}