Middle Characters

using System;
class Program
{
    static void Main(string[] args)
    {
        string st = Console.ReadLine();
        MiddleChar(st);
    }
    public static void MiddleChar(string st)
    {
        if(st.Length%2!=0)
        {
            Console.WriteLine(st[st.Length/2]);
        }
        else
        {
            Console.WriteLine($"{st[st.Length/2-1]}{st[st.Length/2]}");
        }
    }
}