import java.io.*;
import java.math.BigInteger;

public class Main {

    static BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
    static int N = 55;
    static BigInteger[][] dp = new BigInteger[N][N];
    static BigInteger[] a = new BigInteger[N];
    static final String INF = String.valueOf("10000000000000000000000000000");  //28个0
    public static void main(String[] args) throws Exception{
        int n = Integer.valueOf(read.readLine());
        String[] ss = read.readLine().split(" ");
        for(int i = 1; i <= n; i++){
            a[i] = new BigInteger(ss[i - 1]);
        }
        for(int len = 2; len <= n; len++){
            for(int i = 1; i + len - 1 <= n; i++){    //注意， 这里的r小于等于n
                int j = i + len - 1;
                dp[i][j] = new BigInteger(INF);  //初始化为最大值
                if(len == 2) dp[i][j] = new BigInteger("0");
                else {
                    for(int k = i + 1; k < j; k++){
                        dp[i][j] = dp[i][j].min(dp[i][k].add(dp[k][j]).add((a[i].multiply(a[k]).multiply(a[j]))));
                    }
                }
            }
        }

        System.out.println(dp[1][n]);
    }
}