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

int main() 
{
    int n;
    cin >> n;
    vector<string> a(n);
    vector<string> b(n);
    string max = "";  

    for (int i = 0; i < n; i++) 
    {
        cin >> a[i];
        b[i] = a[i];

        string reversed = "";
        for (int j = a[i].size() - 1; j >= 0; j--) 
        {
            reversed += a[i][j];
        }

        if (reversed == b[i]) 
        {
            if (b[i] > max) 
            {
                max = b[i];
            }
        }
    }

    cout << max;
    return 0;
}