const int MAXN = 2014;

class TwoSAT{
private:
	int n;
	vector <int> G[MAXN*2];
	bool mark[MAXN*2];
	int S[MAXN*2], c;

	bool dfs(int x)
	{
		if (mark[x^1]) return false;
		if (mark[x]) return true;
		mark[x] = true;
		S[c++] = x;
		for (int i = 0; i<G[x].size(); i++){
			if (!dfs(G[x][i])) return false;
		}
		return true;
	}
public:
	void init(int n)
	{
		this->n = n;
		for (int i = 0; i<n*2; i++) G[i].clear();
		memset(mark, 0, sizeof(mark));
	}

/*
	Add clause : x==xval or y==yval
	xval and yval are bool
*/
	void add_clause(int x, int xval, int y, int yval)
	{
		x = x*2+xval;
		y = y*2+yval;
		G[x^1].push_back(y);
		G[y^1].push_back(x);
	}

	bool solve()
	{
		for (int i = 0; i<n*2; i+=2){
			if (!mark[i] && !mark[i+1]){
				c = 0;
				if (!dfs(i)){
					while (c>0) mark[S[--c]] = false;
					if (!dfs(i+1)) return false;
				}
			}
		}
		return true;
	}

	void getSolution(bool sol[])
	{
		for (int i = 0; i<n*2; i++) sol[i] = mark[i];
	}
};