#include <iostream>
#include <stdio.h>
#include <vector>
#include <sstream>
#include <string>

using namespace std;

class Ponto {
public:
	int x;
	int y;
	int active;
	int sup;
};

class Retangulo {
public:
    int x;
    int y;
    int id;
    Ponto sup;
    Ponto inf;
};

int nr_rets;
int nr_configs = 0;
int nr_rec = 0;
int area = 0;

bool check_intersections(Retangulo r, vector<Retangulo> colocados){
	if (colocados.size() == 0 || colocados.size() == 1){
		return false;
	}

	//Percorrer retangulos ja colocados
	for (int i=0; i<colocados.size(); i++){

		if (r.sup.x < colocados.at(i).inf.x && r.inf.x > colocados.at(i).sup.x && r.sup.y > colocados.at(i).inf.y && r.inf.y < colocados.at(i).sup.y){
			//Existe interseção
			cout << "Intersetei";
			return true;
		}
	}

	return false;
}

bool check_retangle(vector<Retangulo> colocados, Retangulo r){

	for (int i=0; i<colocados.size(); i++){
		if (r.id == colocados.at(i).id){
			//cout << "oi";
			return true;
		}
	}

	return false;
}

void mostra_pts(vector<Ponto> pts){
  int i;
  for(i=0;i<pts.size();i++){
    cout <<"X:" << pts.at(i).x << "  Y:" << pts.at(i).y << "    Active: "<< pts.at(i).active <<" \n";
  }
  cout << "\n";
}

bool fitting_retangle(int x, int y){
    int area_to_fill = 0;

    area_to_fill = x * y;

    if(area < area_to_fill){
      return true;
    }

    return false;
}

bool is_retangle(vector<Ponto> pts){
	int area_ret;
	int x,y;
	vector<Ponto> active;
	Ponto p;

	for (int i=0; i<pts.size(); i++){
		if (pts.at(i).active == 1){
			p.x = pts.at(i).x;
			p.y = pts.at(i).y;
			p.active = 1;
			active.push_back(p);
		}
	}

	if (active.size() != 2){
		return false;
	}
	else{
		x = active.at(0).x + active.at(1).x;
		y = active.at(0).y + active.at(1).y;
		area_ret = x*y;
	}

	if (area_ret == area){
		return true;
	}

	return false;
}

void recursive(Retangulo r, vector<Retangulo> rets, vector<Ponto> pts, vector<Retangulo> colocados, int x_max, int y_max){

	int tam = pts.size();
	//Percorrer lista de cantos ativos
	for (int i=0; i<tam; i++){
		//Condição de paragem
		if (colocados.size() == nr_rets){
			//mostra_pts(pts);
			if (is_retangle(pts) == true){
				nr_configs++;
			}
			nr_configs++;
			return ;
		}
		if (pts.at(i).active == 1){
			Ponto p,p1;

			pts.at(i).active = 0;

			p.x = pts.at(i).x + r.x;
			p.y = pts.at(i).y;

			p1.x = pts.at(i).x;
			p1.y = pts.at(i).y + r.y;


			if (!check_retangle(colocados,r)){

				r.sup = p1;
				r.inf = p;

				//Verificar se existem interseções entre o retangulo a colocar e os ja colocados
				//if (!check_intersections(r,colocados)){
					cout << "Coloquei o " << r.id << " no ponto " << pts.at(i).x << "," << pts.at(i).y << "\n";

					colocados.push_back(r);

					p1.active = 1;
					p.active = 1;

					pts.push_back(p);
					pts.push_back(p1);

					//update_active_pts(pts);
				//}

			}

			cout << "Colocados: ";
			for (int c = 0; c<colocados.size(); c++){
				cout << colocados.at(c).id << " ";
			}
			cout << "\n";

			for (int j = 0; j<rets.size(); j++){
				if (!check_retangle(colocados,rets.at(j))){
					recursive(rets.at(j), rets, pts, colocados,0,0);
				}
			}

		}

	}

}

int main(){
	string line;
	string buf;
	int indices;
	int id = 1;
	int tam;

	cin >> indices;
	nr_rets = indices;


	vector<Retangulo> rets;
	vector<Retangulo> colocados;

	cin.ignore();
	while(indices != 0){
		getline(cin,line);
		Retangulo r;

		stringstream ss(line);
		vector<string> tokens;

		while (ss >> buf)
            tokens.push_back(buf);

        if (!tokens.empty()){
            istringstream convert(tokens.at(0));
            convert >> r.x;

            istringstream convert1(tokens.at(1));
            convert1 >> r.y;
        }

        r.id = id;

		rets.push_back(r);

		id++;
		indices--;
	}

	//Ponto na origem (0,0)
	vector<Ponto> pts;
	Ponto p;
	p.x = 0;
	p.y = 0;
	p.active = 1;
	pts.push_back(p);

	//Rodar retangulos
	tam = rets.size();
	for (int i=0; i<tam; i++){
		if (rets.at(i).x != rets.at(i).y){
			//Nao e quadrado, logo podemos rodar
			Retangulo r1;
			r1.x = rets.at(i).y;
			r1.y = rets.at(i).x;
			r1.id = rets.at(i).id;
			rets.push_back(r1);
		}
	}

	//Calculo da area total dos retangulos
	for (int i=0;i<rets.size();i++){
		area += (rets.at(i).x * rets.at(i).y);
	}

	for (int i=0; i<rets.size(); i++){
		recursive(rets.at(i),rets,pts,colocados,0,0);
	}

	cout << nr_configs;

	return 0;
}