Vent System

#include <bits/stdc++.h>
using namespace std;

#define cin(vec) for(auto& i : vec) cin >> i
#define cin_2d(vec, n, m) for(int i = 0; i < n; i++) for(int j = 0; j < m && cin >> vec[i][j]; j++);
#define cout(vec) for(auto& i : vec) cout << i << " "; cout << "\n";
#define cout_2d(vec, n, m) for(int i = 0; i < n; i++, cout << "\n") for(int j = 0; j < m && cout << vec[i][j] << " "; j++);
#define cout_map(mp) for(auto& [f, s] : mp) cout << f << "  " << s << "\n";
#define fixed(n) cout << fixed << setprecision(n)
#define Ceil(n, m) (((n) / (m)) + ((n) % (m) ? 1 : 0))
#define fill(vec, value) memset(vec, value, sizeof(vec));
#define Num_of_Digits(n) ((int)log10(n)+1)
#define all(vec) vec.begin(),vec.end()
#define rall(vec) vec.rbegin(),vec.rend()
#define sz(x) int(x.size())
#define fi first
#define se second
#define Pair pair < int, int >
#define ll long long
#define ull unsigned long long
#define Mod  1'000'000'007
#define INF 2'000'000'000
#define all(vec) vec.begin(),vec.end()
#define rall(vec) vec.rbegin(),vec.rend()
#define sz(x) int(x.size())
#define fi first
#define se second
#define Pair pair < int, int >
#define ll long long
#define ull unsigned long long
#define Mod  1'000'000'007
#define INF 2'000'000'000
#define PI acos(-1)

void Code_Crush(){
  ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
  #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
  #endif
}

int main(){
  Code_Crush();
    int n, m, count;
    cin >> n;
    string room, name, dead, sus_room;
    for(int i = 0; i < n && cin >> room; i++);
    cin >> m;
    vector < pair < string, string > > vent(m);
    for(auto& [f, s] : vent) cin >> f >> s;
    cin >> count;
    int reports = count - 3;
    map < string, int > sus;
    for(int i = 0; i < count && cin >> name; i++)sus[name];
    while(reports--){
        cin >> dead >> room;
        sus.erase(dead);
        count--;
        for(int i = 0; i < count; i++){
            cin >> name >> sus_room;
            bool is_sus = (room == sus_room);
            for(auto & [f, s] : vent)
                if((f == sus_room && s == room) || (f == room && s == sus_room)) is_sus = true;
            if(is_sus) sus[name]++;
        }
    }
    int mx_cnt = -1;
    for(auto & [f, s] : sus){
        if(s > mx_cnt) name = f, mx_cnt = s;
        else if(s == mx_cnt) name = "?";
    }
    cout << name << "\n";
  return 0;
}