能量项链//区间DP

#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#define inf 0x7fffffff
using namespace std;
int a[2005],n;
int f[2000][2000],ans=0;
int main() 
{ 
    cin>>n; 
    for(int i=1;i<=n;i++) 
    { 
        scanf("%d",&a[i]);
        a[i+n]=a[i]; 
    } 
    a[2*n+1]=a[1];
    for(int i=2*n;i>=1;i--)
    {
         for(int j=i+1;j<=i+n-1&&j<=2*n;j++)
            for(int k=i;k<j;k++)
            {
                f[i][j]=max(f[i][j],f[i][k]+f[k+1][j]+a[i]*a[k+1]*a[j+1]);
                ans=max(ans,f[i][j]);
            }        
    }
    cout<<ans;
    puts("");
    return 0;
}