Problem: Polycarp is currently developing a project in Vaja language and using a popular dependency management system called Vamen. From Vamen's point of view both Vaja project and libraries are treated projects for simplicity.

A project in Vaja has its own uniqie non-empty name consisting of lowercase latin letters with length not exceeding 10 and version — positive integer from 1 to 106. Each project (keep in mind that it is determined by both its name and version) might depend on other projects. For sure, there are no cyclic dependencies.

You're given a list of project descriptions. The first of the given projects is the one being developed by Polycarp at this moment. Help Polycarp determine all projects that his project depends on (directly or via a certain chain). 

It's possible that Polycarp's project depends on two different versions of some project. In this case collision resolving is applied, i.e. for each such project the system chooses the version that minimizes the distance from it to Polycarp's project. If there are several options, the newer (with the maximum version) is preferred. This version is considered actual; other versions and their dependencies are ignored.

More formal, choose such a set of projects of minimum possible size that the following conditions hold: 

  * Polycarp's project is chosen; 
  * Polycarp's project depends (directly or indirectly) on all other projects in the set; 
  * no two projects share the name; 
  * for each project x that some other project in the set depends on we have either x or some y with other version and shorter chain to Polycarp's project chosen. In case of ties the newer one is chosen. 



Output all Polycarp's project's dependencies (Polycarp's project itself should't be printed) in lexicographical order.

Input

The first line contains an only integer n (1 ≤ n ≤ 1 000) — the number of projects in Vaja.

The following lines contain the project descriptions. Each project is described by a line consisting of its name and version separated by space. The next line gives the number of direct dependencies (from 0 to n - 1) and the dependencies themselves (one in a line) in arbitrary order. Each dependency is specified by its name and version. The projects are also given in arbitrary order, but the first of them is always Polycarp's. Project descriptions are separated by one empty line. Refer to samples for better understanding.

It's guaranteed that there are no cyclic dependencies. 

Output

Output all Polycarp's project's dependencies in lexicographical order.

Examples

Input

4
a 3
2
b 1
c 1
 
b 2
0
 
b 1
1
b 2
 
c 1
1
b 2


Output

2
b 1
c 1


Input

9
codehorses 5
3
webfrmk 6
mashadb 1
mashadb 2
 
commons 2
0
 
mashadb 3
0
 
webfrmk 6
2
mashadb 3
commons 2
 
extra 4
1
extra 3
 
extra 3
0
 
extra 1
0
 
mashadb 1
1
extra 3
 
mashadb 2
1
extra 1


Output

4
commons 2
extra 1
mashadb 2
webfrmk 6


Input

3
abc 1
2
abc 3
cba 2

abc 3
0

cba 2
0


Output

1
cba 2

Note

The first sample is given in the pic below. Arrow from A to B means that B directly depends on A. Projects that Polycarp's project «a» (version 3) depends on are painted black.

<image>

The second sample is again given in the pic below. Arrow from A to B means that B directly depends on A. Projects that Polycarp's project «codehorses» (version 5) depends on are paint it black. Note that «extra 1» is chosen instead of «extra 3» since «mashadb 1» and all of its dependencies are ignored due to «mashadb 2».

<image>

Solution (in JAVA):

Solution:
//package vkcup;

import java.io.*;
import java.util.*;

/**
 * Created by Telnov Sergey on 24.02.2018.
 */
public class C {

    int n;
    FastReader reader = new FastReader();
    Project[] projects;
    ArrayList<Integer>[] graph;
    HashMap<String, Integer> info = new HashMap<>();
    private int[] dists;
    HashMap<String, List<Project>> used = new HashMap<>();

    class Project {
        final int version;
        final String name;
        final String fullName;

        Project(String name, int version, String fillName) {
            this.name = name;
            this.version = version;
            this.fullName = fillName;
        }
    }

    private int scanProject() throws IOException {
        String name = reader.next();
        int version = reader.nextInt();

        String fullName = name + " " + version;
        Project that;
        if (info.containsKey(fullName)) {
            return info.get(fullName);
        } else {
            int index = info.size();
            graph[index] = new ArrayList<>();
            that = new Project(name, version, fullName);
            projects[index] = that;
            info.put(fullName, index);
            return index;
        }
    }

    private boolean canGo(int curr) {
        for (Project sameProject : used.get(projects[curr].name)) {
            int index = info.get(sameProject.fullName);
            if (dists[index] == Integer.MAX_VALUE)
                continue;
            if (dists[index] == dists[curr] && sameProject.version < projects[curr].version) {
                dists[index] = Integer.MAX_VALUE;
            } else if (dists[index] == dists[curr] && sameProject.version > projects[curr].version || dists[curr] > dists[index]) {
                dists[curr] = Integer.MAX_VALUE;
                return false;
            }
        }
        return true;
    }

    private void bfs() {
        dists = new int[n];
        Arrays.fill(dists, Integer.MAX_VALUE);
        dists[0] = 0;

        Queue queue = new ArrayDeque();
        queue.add(0);

        used.put(projects[0].name, new LinkedList<Project>() {{ add(projects[0]); }});

        while (!queue.isEmpty()) {
            int curr = (int) queue.poll();
            if (dists[curr] == Integer.MAX_VALUE || !canGo(curr))
                continue;

            for (int el : graph[curr]) {
                if (dists[el] == Integer.MAX_VALUE) {
                    if (used.containsKey(projects[el].name)) {
                        int index = info.get(used.get(projects[el].name).get(0).fullName);
                        if (dists[index] <= dists[curr]) {
                            continue;
                        } else {
                            used.get(projects[el].name).add(projects[el]);
                        }
                    } else {
                        used.put(projects[el].name, new LinkedList<Project>() {{ add(projects[el]); }});
                    }
                    dists[el] = dists[curr] + 1;
                    queue.add(el);
                }
            }
        }
    }

    public void run() throws IOException {
        n = reader.nextInt();

        graph = new ArrayList[n];
        projects = new Project[n];

        for (int i = 0; i != n; i++) {
            final int index = scanProject();

            int m = reader.nextInt();
            for (int j = 0; j != m; j++) {
                final int nextIndex = scanProject();
                graph[index].add(nextIndex);
            }
        }
        bfs();
        List<String> ans = new ArrayList<>();
        for (int i = 1; i != n; i++) {
            if (dists[i] != Integer.MAX_VALUE) {
                ans.add(projects[i].fullName);
            }
        }
        ans.sort(null);
        FastWriter writer = new FastWriter();
        writer.println(ans.size());
        for (String line : ans) {
            writer.println(line);
        }
        writer.close();
    }

    public static void main(String[] args) throws IOException {
        new C().run();
    }

    private static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public FastReader(String fileName) throws IOException {
            br = new BufferedReader(new InputStreamReader(
                    new FileInputStream(fileName))
            );
        }

        public String next() throws IOException {
            while (st == null || !st.hasMoreElements()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException {
            return Integer.parseInt(next());
        }

        public long nextLong() throws IOException {
            return Long.parseLong(next());
        }

        public int nextIndex() throws IOException {
            return nextInt() - 1;
        }
    }
    private static class FastWriter {
        public FastWriter() {
            bw = new BufferedWriter(
                    new OutputStreamWriter(System.out)
            );
            sb = new StringBuilder();
        }

        public FastWriter(String fileName) throws IOException {
            bw = new BufferedWriter(new OutputStreamWriter(
                    new FileOutputStream(fileName))
            );
            sb = new StringBuilder();
        }

        public void println(final int i) {
            sb.append(i).append("\n");
        }

        public void println(String line) {
            sb.append(line).append("\n");
        }

        public void println(final long l) {
            sb.append(l).append("\n");
        }

        public void print(final int i) {
            sb.append(i).append(" ");
        }

        public void close() throws IOException {
            bw.write(sb.toString());
            bw.flush();
            bw.close();
        }

        private BufferedWriter bw;
        private StringBuilder  sb;
    }
}