#include <algorithm>
#include <iostream>
#include <set>
#include <vector>

std::vector<std::vector<int> > graph;
std::vector<int> answ;
std::vector<int> odd_nodes;

void DFS(int curr_node) {
    for (int i = 1; i != graph[curr_node].size(); ++i) {
        if (graph[curr_node][i] != 0) {
            --graph[curr_node][i];
            --graph[i][curr_node];
            DFS(i);
            answ.push_back(curr_node);
        }
    }
}

int main() {
    int n;
    std::cin >> n;
    graph.resize(n + 1);
    for (int i = 1; i != n + 1; ++i) {
        graph[i] = std::vector<int>(n + 1);
    }
    int num_odd_degree = 1;
    for (int i = 1; i != n + 1; ++i) {
        int count;
        std::cin >> count;
        for (int j = 0; j != count; ++j) {
            int second, weight;
            std::cin >> second >> weight;
            graph[i][second] += 1;
        }
        if (count % 2) {
            num_odd_degree = i;
            odd_nodes.push_back(i);
        }
    }
    DFS(num_odd_degree);
    std::cout << answ.size() << "\n";
    std::reverse(answ.begin(), answ.end());
    if (odd_nodes.size() == 0)
        answ.push_back(num_odd_degree);
    else if (num_odd_degree == odd_nodes[0])
        answ.push_back(odd_nodes[1]);
    else
        answ.push_back(odd_nodes[0]);
    for (auto elem : answ)
        std::cout << elem << " ";
}