#include <fstream>
#include <queue>

class InParser
{
#pragma warning(disable:4996)
private:
	FILE* fin;
	char* buff;
	int sp;
	char read()
	{
		++sp;
		if (sp == 4096)
		{
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}
public:
	InParser(const char* nume)
	{
		sp = 4095;
		buff = new char[4096];
		fin = fopen(nume, "r");
	}
	InParser& operator >> (int& n)
	{
		int sgn = 1;
		char c;
		while (!isdigit(c = read()) && c != '-');
		if (c == '-')
		{
			n = 0;
			sgn = -1;
		}
		else
			n = c - '0';
		while (isdigit(c = read()))
			n = n * 10 + c - '0';
		n *= sgn;
		return *this;
	}
};

InParser fin("interclasari.in");
std::ofstream fout("interclasari.out");

std::priority_queue <int> q;

int k, n, x;

int main()
{
	fin >> k;
	while (k--)
	{
		fin >> n;
		for (int i = 1; i <= n; ++i)
		{
			fin >> x;
			q.push(-x);
		}
	}
	fout << q.size() << "\n";
	while (!q.empty())
	{
		fout << -q.top() << " ";
		q.pop();
	}
	fout << "\n";
	fout.close();
	return 0;
}