#include <stdio.h>
#define NMAX 512
#define LL long long
#define INF 99999999999999999LL
int N,d[NMAX];
LL T[NMAX][NMAX];
int main()
{
    int i,j,k;
    freopen("podm.in","r",stdin);
    freopen("podm.out","w",stdout);
    scanf("%d",&N);
    for (i=0;i<=N;++i) scanf("%d",&d[i]);
    for (j=1;j<=N;++j)
    {
        T[j][j]=0;
        for (i=j-1;i;i--)
        {
            LL min=INF,aux=(LL)d[i-1]*d[j];;
            for (k=i;k<j;++k)
            {
                LL ret=T[i][k]+T[k+1][j]+aux*d[k];
                if (ret<min) min=ret;
            }
            T[i][j]=min;
        }
    }
    printf("%lld",T[1][N]);
    return 0;
}