#include <bits/stdc++.h>
using namespace std;
ifstream fin("podm.in");
ofstream fout("podm.out");
long long n,dp[501][501],i,j,k,l,x,y;
pair<int,int> v[501];
int main()
{
    fin>>n;
    fin>>v[1].first;
    for(i=1;i<=n;i++){
        fin>>v[i].second;
        v[i+1].first = v[i].second;
    }
    for(i=1;i<=n;i++){
        for(j=1;j<=n;j++)
            dp[i][j] = LLONG_MAX;
        dp[i][i] = 0;
    }

    for(i=1;i<n;i++){
        dp[i][i+1] = v[i].first*v[i].second*v[i+1].second;
    }
    for(l=3;l<=n;l++){
        for(i=1;i<=n-l+1;i++){
            j = i+l-1;
            for(k=i;k<j;k++){
                dp[i][j] = min(dp[i][j], dp[i][k]+dp[k+1][j]+v[i].first*v[k].second*v[j].second);
            }
        }
    }
    fout<<dp[1][n];
    return 0;
}