#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <algorithm>
#include <ctime>
#include <string>
#include <queue>
#include <unordered_map>
#include <map>
#include <set>

#define prev asjdja

typedef long long ll;

using namespace std;

const int INF = 1e6 * 6.25 + 7;

void print(vector<int> s){
    for (int i = 0; i < s.size(); i++)
        cout << s[i] << " ";
    cout << "\n";
}


int main()
{
    //freopen("a.in", "r", stdin);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, k;
    cin >> n >> k;
    map<string, string> mapa;
    for (int i = 0; i < n; i++){
        string s1, s2;
        cin >> s1 >> s2;
        mapa[s1] = s2;
    }
    cin >> n;
    vector<string> s(n);
    for (int i = 0; i < n; i++)
        cin >> s[i];
    sort(s.begin(), s.end());
    int cnt = 1;
    set<pair<int, string> > lst;
    map<string, int> mapa2;
    for (int i = 1; i < n; i++){
        if (s[i] != s[i - 1]){
            lst.insert(make_pair(-cnt, s[i - 1]));
            mapa2[s[i - 1]] = cnt;
            cnt = 1;
        }
        else
            cnt++;
    }
    mapa2[s.back()] = cnt;
    lst.insert(make_pair(-cnt, s.back()));
    vector<string> answer;
    while (lst.size() > 0){
        pair<int, string> v = *(lst.begin());
        lst.erase(v);
        v.first *= -1;
        if (v.first < k || mapa.find(v.second) == mapa.end()){
            for (int i = 0; i < v.first; i++)
                answer.push_back(v.second);
            mapa2[v.second] = 0;
            continue;
        }
        pair<int, string> u = make_pair(0, mapa[v.second]);
        if (mapa2[u.second] != 0)
            pair<int, string> u = make_pair(-mapa2[u.second], u.second);
        lst.erase(u);
        u.first -= v.first / k;
        v.first %= k;
        mapa2[v.second] = v.first;
        mapa2[u.second] = u.first;
        lst.insert(u);
        v.first *= -1;
        lst.insert(v);
    }
    cout << answer.size() << endl;
    for (int i = 0; i < answer.size(); i++)
        cout << answer[i] << "\n";
    return 0;
}