using System;

public class Program

{

    public static void Main()

    {

        int n = Convert.ToInt16(Console.ReadLine());

            int [,] a = new int[n,n];

        int k = 0;

        int m = 0;

        for (int i=0; i<n; i++)

            for (int j=0; j<n; j++)

            if ((a[i,j]<0)&(i=j))

        {

            m = k;

            k = a[i,j];

        }   

        Console.WriteLine(m);

    }

}