#include <bits/stdc++.h>
using namespace std;
bool is_prefix(string s, string comp) {
  bool res = false;
  int sz = s.size();
  int comp_sz = comp.size();
  if (sz > comp_sz)
    return res;
  else {
    res = true;
    for (int i = 0; i < sz; i++) {
      if (s[i] != comp[i]) {
        res = false;
        break;
      }
    }
  }
  return res;
}
int main(int argc, char* argv[]) {
  int n;
  string s;
  vector<string> res;
  cin >> s;
  cin >> n;
  for (int i = 0; i < n; i++) {
    string t;
    cin >> t;
    if (is_prefix(s, t)) res.push_back(t);
  }
  if (res.size() == 0) {
    cout << s;
  } else {
    sort(res.begin(), res.end());
    cout << res[0];
  }
  return 0;
}
