备注：
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#include <queue>
#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
#include <map>
using namespace std;
#define int long long
const int N = 1e3 + 10;
const int INF = 0x3f3f3f3f;
int n;
int a[N];
int dp[N][N][41];
void calc(int t[], int s)
{
	int k = 0;
	for(int i = 0; i < 40; i++)
	{
		t[i] = t[i] * s + k;
		k = t[i] / 10;
		t[i] %= 10;
	}
}
void add(int t[], int dp[])
{
	for(int i = 0; i < 40; i++)
	{
		t[i] += dp[i];
		t[i+1] += t[i] / 10;
		t[i] %= 10;
	}
}
bool cmp(int t[], int dp[])
{
	for(int i = 40; i >= 0; i--)
	{
		if(t[i] > dp[i])
			return false;
		else if(t[i] < dp[i])
			return true;
	}
	return false;
}
void print(int dp[])
{
	int k = 40;
	while(dp[k] == 0)
		k--;
	for(int i = k; i >= 0; i--)
	{
		cout << dp[i];
	}
	cout << endl;
}
signed main()
{
	//freopen(".in", "r", stdin);
	//freopen(".out", "w", stdout);
	cin >> n;
	for(int i = 1; i <= n; i++)
	{
		cin >> a[i];
	}
	for(int k = 3; k <= n; k++)
	{
		for(int l = 1; l <= n-k+1; l++)
		{
			int r = l+k-1;
			dp[l][r][40] = 1;
			for(int i = l+1; i < r; i++)
			{
				int t[41];
				memset(t, 0, sizeof(t));
				t[0] = 1;
				calc(t, a[i]);
				calc(t, a[l]);
				calc(t, a[r]);
				add(t, dp[l][i]);
				add(t, dp[i][r]);
				if(cmp(t, dp[l][r]))
					memcpy(dp[l][r], t, sizeof(t));
			}
		}
	}
	print(dp[1][n]);
	return 0;
}