#include<bits/stdc++.h>
using namespace std;
string origin,s,ans;
int n,len;
int main(){
	cin>>origin>>n;
	len=origin.length();
	for(int i=1;i<=n;++i){
		cin>>s;
		bool find=true;
		for(int j=0;j<len;++j){
			if(origin[j]!=s[j]){
				find=false;
				break;
			}
		}
		if(find&&(ans.length()==0||s.length()<ans.length())){
			ans=s;
		}
	}
	if(ans.length()==0){
		cout<<origin;
	}else{
		cout<<ans;
	}
	return 0;
}