10分求调

#include<bits/stdc++.h>
using namespace std;
int n;
string s;
string ans;
int main(){
	cin>>n;
	while(n--){
		cin>>s;
		string s1=s;
		reverse(s.begin(),s.end());
		if(s1==s) ans=max(ans,s1);
	}
	cout<<ans<<endl;
	return 0;
}