import java.util.Arrays;

public class Tri 
{
  public static void main(String[] args) 
  {
    int n = 0;
    int j = 0;
    int[] tabN = new int[args.length];
    for (String i : args ) 
    {
      n = Integer.parseInt(i);
      tabN[j] = n;
      j++;
    }
    Arrays.sort(tabN);

    for (int i : tabN ) 
    {
      System.out.print(i);
    }
  }
}