#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <cmath>
//#include<bits/stdc++.h>
//#define int long long
#define pb push_back
using namespace std;
bool isInt(char a)
{
    for(int i = 0; i < 10; i++)
        if(a - '0' == i)
            return true;
    return false;
}
signed main()
{
    int t;
    cin >> t;
    map<int,int> schools;
    for(int i = 0; i <= t; i++)
    {
        string s,str;
        getline(cin,s);
        for(int j = 0; j < s.length(); j++)
        {
            bool f = false;
            while(isInt(s[j]))
            {
                str += s[j];
                f = true;
                j++;
            }
            if(f)
                j = s.length()+1;
        }
        if(str.length() > 0 && schools.find(stoi(str)) == schools.end())
            schools.emplace(stoi(str),1);
        else if(str.length() > 0 && schools.find(stoi(str)) != schools.end())
        {
            auto it = schools.find(stoi(str));
            it->second++;
        }
    }
    vector<int> ans;
    for(auto i: schools)
        if(i.second <= 5)
            ans.pb(i.first);
    cout << ans.size() << "\n";
    for(auto i: ans)
        cout << i << "\n";
}