#include 
using namespace std;
ifstream cin("spioni.in");
ofstream cout("spioni.out");
void solve(string s)
{
    /// base case
    if(s.length() <= 2)
    {
        cout << s;
        return;
    }
    ///generam cele doua stringuri.
    string a = "", b = "";
    for(int i = 0;i>c; /// absolut inutil.
    string s; cin >> s;
    solve(s);
    return 0;
}