#include <cstdio>
#include <algorithm>
#define LL long long
#define N 505

using namespace std;
LL n,i,k,L,R,d[N],D[N][N];
int main()
{
    freopen("podm.in","r",stdin);
    freopen("podm.out","w",stdout);
    scanf("%lld",&n);
    for(i=0;i<=n;i++)
        scanf("%lld",&d[i]);
    for(i=1;i<n;i++)
        D[i][i+1]=d[i-1]*d[i+1];
    for(k=3;k<=n;k++)
        for(L=1,R=k;R<=n;L++,R++)
        {
            D[L][R]=D[L][L+1]+D[L+2][R];
            for(i=L+2;i<R-1;i++)
                D[L][R]=min(D[L][R],D[L][i]+D[i+1][R]);
            D[L][R]+=d[L-1]*d[R];
        }
    printf("%lld",D[1][n]);
    return 0;
}