#include <stdio.h>
#define MIL 1000000000
#define MAX 50


int N, cislo;

struct ret
{
	unsigned int val[MAX];
	int pocetsynu;

	ret() { for (int i = 1; i < MAX; i++) val[i] = 0; val[0] = 1; pocetsynu = 0; }

	void sum(ret& v, ret& w)
	{
		for (int i = 0; i < MAX; i++) val[i] = 0;
	 	for (int i = 0; i < MAX; i++)
			val[i] += v.val[i] + w.val[i];
		for (int i = 0; i < MAX-1; i++)
		{
			val[i+1] += val[i] / MIL;
			val[i] %= MIL;
		}
	}

	void mul(ret&v, ret& w)
	{
		for (int i = 0; i < MAX; i++) val[i] = 0;
		for (int i = 0; i < MAX; i++)
		{
			for (int j = 0; j < MAX-1 - i; j++)
			{
				long long int a = v.val[i];
				long long int b = w.val[j];
				long long int c = a * b;
				val[i+j+1] += c / MIL;
				val[i+j] += c % MIL;				
			}
		}
		for (int i = 0; i < MAX-1; i++)
		{
			val[i+1] += val[i] / MIL;
			val[i] %= MIL;
		}
	}

	void tiskni()
	{
		int pozice = MAX-1;
		for (; pozice > 0; pozice--)
			if (val[pozice] != 0)
				break;
		printf("%d", val[pozice]);
		for (int i = pozice - 1; i >= 0; i--)
		{
			printf("%09d", val[i]);
		}
	}
};
ret pascal[500][500];

struct node
{
	node* l;
	node* r;
	int cislo;
	int pocet;

	node() { l = r = NULL; pocet = 1; }
};

node koren;


void add(node* root, int in);
ret projdi(node* root);

int main()
{
	pascal[0][0].val[0] = 1;
	for (int i = 1; i < 105; i++)
	{
		for (int j = 0; j <= i; j++)
		{
			if (j == 0 || j == i)
				pascal[i][j].val[0] = 1;
			else
				pascal[i][j].sum(pascal[i-1][j-1],pascal[i-1][j]);
			/*printf("pascal[%d][%d] = ", i, j);
			pascal[i][j].tiskni();
			printf("\n");*/
		}
	}

	while (1)
	{

	scanf("%d", &N); 
	if (N == 0)
		return 0;
	scanf("%d", &cislo);
	koren.cislo = cislo;
	koren.l = koren.r = NULL;
	for (int i = 1; i < N; i++)
	{
		scanf("%d", &cislo);
		add(&koren, cislo);
	}

	ret result = projdi(&koren);
	result.tiskni();
	printf("\n");
	}
	return 0;
}

void add(node* root, int in)
{
	if (root->cislo > in)
	{
		if (root->l)
		{
		//	printf("adding %d to left\n", in);
			add(root->l,in);
		}
		else
		{
		//	printf("adding %d to left\n", in);
			root->l = new node;
			root->l->cislo = in;
		}
	}
	else
	{
		if (root->r)
		{
		//	printf("adding %d to right\n", in);
			add(root->r,in);
		}
		else
		{
			//printf("adding %d to right\n", in);
			root->r = new node;
			root->r->cislo = in;
		}
	}
}

ret projdi(node* root)
{
	//printf("projdi: %d:\n", root->cislo);
	ret l; ret r;
	if (root->l)
		l = projdi(root->l);
	if (root->r)
		r = projdi(root->r);

	ret result, result2;
	result.pocetsynu = l.pocetsynu + r.pocetsynu + 1;
	result2.mul(l,r);
	//result2.tiskni();
	//printf(" mul\n");
	//pascal[result.pocetsynu-1][l.pocetsynu].tiskni(); 
	//printf(" mul %d %d\n", result.pocetsynu-1, l.pocetsynu);
	result.mul(result2, pascal[result.pocetsynu-1][l.pocetsynu]);
	//printf("%d result: ", root->cislo);
	//result.tiskni();
	//printf("\n");
	return result;
}