#include <fstream>

using namespace std;
ifstream cin ("podm.in");
ofstream cout ("podm.out");
long long a[505],i,n,ind,m,s;
int main()
{
    cin>>n;
    for(i=1; i<=n+1; i++)cin>>a[i];
    n=n+1;
    s=0;
    while(n>2)
    {
        m=a[2];
        ind=2;
        for(i=3; i<n; i++)if(a[i]>m)
            {
                ind=i;
                m=a[i];
            }
        s+=a[ind-1]*a[ind]*a[ind+1];
        for(i=ind;i<n;i++)swap(a[i],a[i+1]);
        n--;
    }
    cout<<s;
    return 0;
}