#include <iostream>
#include <vector>
#include <algorithm>
#include <string>

using namespace std;

int num[30];
vector<string> facs;

string div(const string &A, int b)
{
    string s = "";
    int c = 0, t = 0;
    for (int i = 0; i < A.size(); i ++)
    {
        c = t * 10 + (A[i] - '0');
        t = c % b;
        c /= b;
        if (c == 0 && s.size() == 0) continue;
        else s += (c + '0');
    }
    return s;
}

string mul(const string &A, int b)
{
    string s = "";
    int c = 0, t = 0;
    for (int i = A.size() - 1; i >= 0; i --)
    {
        c = (A[i] - '0') * b + t;
        s += (c % 10 + '0');
        t = c / 10;
    }
    while (t)
    {
        c = t % 10;
        s += (c + '0');
        t /= 10;
    }
    reverse(s.begin(), s.end());
    return s;
}

void cal()
{
    facs.push_back("0");
    facs.push_back("1");
    facs.push_back("2");
    string tmp = "2";
    for (int i = 3; i <= 26 * 12; i ++)
    {
        tmp = mul(tmp, i);
        facs.push_back(tmp);
    }
}

int main()
{
    cal();
    int n;
    while (cin >> n && n)
    {
        string A = "";
        int sum = 0;
        for (int i = 1; i <= n; i ++)
        {
            cin >> num[i];
            sum += num[i];
        }
        A = facs[sum];
        for (int i = 1; i <= n; i ++)
            for (int j = 2; j <= num[i]; j ++)
                A = div(A, j);
        cout << A << endl;
    }
    return 0;
}