#include<cstdio>
#include<algorithm>
using namespace std;
int n,i,j,k,d[501];
long long dp[501][501];
int main()
{
    freopen("podm.in","r",stdin);
    freopen("podm.out","w",stdout);
    scanf("%d",&n);
    for(i=0;i<=n;++i) scanf("%d",&d[i]);
    for(i=1;i<n;++i)
        for(j=i+1;j<=n;++j)
        {
            long long A=1LL<<60;
            int D=d[j-i-1]*d[j];
            for(k=j-i;k<j;++k)
                A=min(A,dp[j-i][k]+dp[k+1][j]+1LL*D*d[k]);
            dp[j-i][j]=A;
        }
    printf("%lld ",dp[1][n]);
    return 0;
}