using System;
using System.Linq;
namespace ConsoleApp157
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] arr = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int current = 0;
            for(int i=0;i<arr.Length;i++)
            {
                current = arr[i];
                if(current==arr[i+1])
                {
                    Console.WriteLine();
                }
            }
        }
    }
}