#include <string>
#include <cstdlib>
#include <utility>

using std::string;
typedef unsigned long long priority_type;
typedef unsigned long long key_type;
#define RAND_MAX (1 << 62)
class line;
typedef std::pair<line*, line*> two_lines;

// Treap node representation of a line
class line {
	priority_type priority;
	key_type key;
	string text;
	line *left, *right;

public:
	line(priority_type _p, string _t) : priority(_p), text(_t) {}

	two_lines split(string s) { return two_lines(nullptr, nullptr); }
	void join(line *l) {
		// Take minimum of priorities of roots
		// Join subtrees
	}

	line* find(key_type k) {
		if(k < key) {
			if(left != nullptr)
				return left->find(k);
			else
				return nullptr;
		}
		else if(k > key) {
			if(right != nullptr)
				return right->find(k);
			else
				return nullptr;
		}
		else
			return this;
	}
};

// Treap representation of a file
struct file {
	line* root;

	file() {
		srand(120);
		root = nullptr;
	}
	void insert(string s) {
		line *l = new line(rand(), s);

		if(root == nullptr) {
			root = l;
			return;
		}

		auto two = root->split(s);
		two.first->join(l);
		two.first->join(two.second);
	}
	void remove(string s) {
		auto two = root->split(s);
		two.first = two.first->split(s).first; // TODO sharp split
		two.first->join(two.second);
	}
	line* find(key_type k) {
		return root->find(k);
	}
};