hdu 1287

import java.util.*;
import java.math.*;

public class Main {
	
   public static void main(String[]args)
   {
	   Scanner in =  new Scanner(System.in);
	   
	   while(in.hasNext())
	   {
		   int n = in.nextInt();
		   int array[] = new int[n];
		   for(int i=0;i<n;i++)
			   array[i]=in.nextInt();
		   
		   for(int i=0+'A';i<=0+'Z';i++)
		   {
			   boolean flag = false;
		      for(int j=0;j<n;j++)
		      {
		    	  int temp = array[j]^i;
		    	  if(temp<0+'A'||temp>0+'Z')
		    	  {
		    		  flag = true; break;
		    	  }
		      }
		      if(!flag)
		      {
		    	  String s="";
		    	  for(int j=0;j<n;j++)
		    	  {
		    		  int temp = array[j]^i;
		    		  s = s+(char)(temp);
		    	  }
		    	  System.out.println(s);
		    	  
		      }
		   }
	   }
   }
}