#include <iostream>
#include <map>
#include <string>
#include <vector>
using namespace std;

int main()
{
    map<string, bool> mapa;
    string s;
    cin >> s;
    
    int n;
    cin >> n;
    vector<string> words;
    for(int i = 0; i < n; i++) {
        string x;
        cin >> x;
        words.push_back(x);
        
        mapa[x] = true;
    }
    
    if(mapa[s] == false) {
        cout << s << endl;
    }
    else {
        for(int i = 1; i <= n + 1; i++) {
            string tmp = s + to_string(i);
            
            if(mapa[tmp] == false) {
                cout << tmp << endl;
                break;
            }
        }
    }
    
    
    
    
    
    
    return 0;
}