B. Find The Imposter 2

#include <bits/stdc++.h>

using namespace std ;
#define sz(s) int(s.size())
typedef long long ll ;
#define all(v) v.begin() , v.end()

void ABDEL3AL () {
    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() {
    ABDEL3AL() ;
    int n ; cin >> n ;
    map<string, int> mp;
    while (n--) {
        for (auto &i: mp) {
        string col;
        cin >> col, mp[col]++;
        string room;
        cin >> room;
        int k;
        cin >> k;
        while (k--) cin >> col, mp[col]++;
        }
    }
    string imp ;
    int Min = INT_MAX ;
    for (auto& i : mp)
        if (i.second < Min) Min = i.second , imp = i.first ;
    cout << imp ;
    return 0;
}