#include <iostream>
#include <vector>

using namespace std;

typedef unsigned long long int cislo;

struct bst {
	int n;
	bst *left;
	bst *right;
	bst(int num){ n = num; left = NULL; right = NULL; }
	~bst() { if(left){delete left;}; if(right){delete right;}; }
};

int size(bst *tree)
{
	if(tree == NULL)
		return 0;

	return (1 + size(tree->left) + size(tree->right));
}

void treeins(bst *&tree, int n)
{
	if(tree == NULL){
		tree = new bst(n);
	}else{
		if(tree->n > n){
			treeins(tree->left, n);
		}else{
			treeins(tree->right, n);
		}
	}
}

cislo pocet(cislo a, cislo b)
{
	if(a == 0 || b == 0)
		return 1;

	if(b==1)
		return 1;

	if(a==1)
		return b;
	
	cislo sum = 0;

	for(cislo i = 1; i <= b; i++){
		sum += pocet(a-1,i);
	}

	return sum;
}

cislo perm(bst *tree)
{
	if(tree == NULL)
		return 1;

	return pocet(size(tree->left), (size(tree->right))+1)*perm(tree->left)*perm(tree->right);
}

int main(void)
{
	int n;
	int tmp;
	bst *tree;

	while(true){
		cin >> n;
		if(n == 0)
			break;

		for(int i = 0; i < n; i++){
			cin >> tmp;
			treeins(tree, tmp);
		}

		cislo t = perm(tree);
		cout << t << "\n";
		tree = NULL;
	}

	
	return 0;
}