#include <bits/stdc++.h>

using namespace std;

int dp[100001];
int back[100001];
vector <int> answer;

int main(int argc, char const *argv[])
{
	ifstream fin ("input");
	ofstream fout ("output");
	int n, l;
	fin >> n >> l;
	for (int i = 2; i<=n; ++i)
		dp[i] = (1<<29);
	back[1] = 1;
	for (int i = 1; i<=l; ++i)
	{
		int m;
		fin >> m;
		for (int j = 1; j<=m; ++j)
		{
			int target, source, cost;
			fin >> source >> target >> cost;
			if (dp[target] > dp[source] + cost)
			{
				dp[target] = dp[source] + cost;
				back[target] = source;
			}
		}
	}
	if (dp[n] == (1<<29))
		fout << "Impossible";
	else
	{
		int where = n;
		while (where != back[where])
		{
			answer.push_back(where);
			where = back[where];
		}
		answer.push_back(1);
		reverse(answer.begin(), answer.end());
		for (auto x:answer)
			fout << x << ' ';
		fout << '\n' << dp[n];
	}
	return 0;
}