#include<cstdio>
#define syy myson
using namespace std;
int n,ans,a[101],vis[101],i,j;
int Main()
{
	freopen("energy.in","w",stdin);freopen("energy.out","w",stdout);
	scanf("%d",&n);
	for(i=1;i<=n;i++)scanf("%d",&a[i]);
	for(i=1;i<n;i++)
	{
		int minn=1001,num=0;
		for(j=1;j<=n;j++)
		{
			if(!vis[j])if(minn>a[j])
			{
				minn=a[j];
				num=j;
			}
		}
		int l=num-1,r=num+1;
		if(!l)l=n;
		if(r>n)r=1;
		while(vis[l])
		{
			l--;
			if(!l)l=n;
		}
		while(vis[r])
		{
			r++;
			if(r>n)r=1;
		}
		int anss=a[l]*a[num]*a[r];
		ans+=anss;
		vis[num]=1;
	}
	printf("%d",ans);
	return 0;
}
int main(){;}
int syy=Main();