using System;
using System.Text;

public class Test
{
  public static void Main()
  {
    var s = Console.ReadLine();
    var sb = new StringBuilder();

    Func<int, bool> check = (int i) => i >= 0 && i < s.Length && Char.IsLetterOrDigit(s[i]);

    for (var q=0; q<s.Length; )
      if (Char.IsLetterOrDigit(s[q]) && !check(q-1) && !check(q+1))
    	while (++q<s.Length && !Char.IsLetterOrDigit(s[q]));
      else
        sb.Append(s[q++]);

    Console.WriteLine(sb.ToString());
  }
}