// 字串資料之比對
import java.io.*;
public class n1a {
        public static void main(String args[]) throws Exception
        {  //程式進入點
           String getbr;
           int i,j,pt;
	   int cnt_a,cnt_b;//A B情況的計數器
	   char now_a,now_b;//放兩個字串被取出來的那個字母
	   String stra="",strb=""; //分別放兩個字串
           BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
	   while (true)
	   {
		   System.out.print("請輸入兩個字串：");
		   getbr = br.readLine();
		    if (getbr.equals("0")) //判斷結束
                    {
				System.out.println("結束！");
				return;
		    }
		   //找空白分隔兩個字串
		   pt=getbr.indexOf(' ');
		   if (pt<0)
		   {
			   System.out.println("非兩個字串!");
			   continue;
		   }
		   stra=getbr.substring(0,pt);
		   strb=getbr.substring(pt+1);
		   if (stra.length()!=strb.length())
		   {
			   System.out.println("不等長!");
			   continue;
		   }
		   //System.out.print("stra="+stra+ " strb="+strb);
		   stra=stra.toUpperCase(); //換大寫
		   strb=strb.toUpperCase();
		   cnt_a=0;
		   cnt_b=0;
		   for (i=0;i<stra.length();i=i+1)
		   {
			 now_a=stra.charAt(i);
			 j=strb.indexOf(now_a);
			if (j>=0)
			{
				if (i==j) cnt_a=cnt_a+1;
				else	cnt_b=cnt_b+1;
			}
		   }
		   if (cnt_a>0) System.out.print(cnt_a+"A");
		   if (cnt_b>0) System.out.print(cnt_b+"B");
		   if (cnt_a==0&&cnt_b==0) System.out.print("無相同字元");
		   System.out.println();
	   }//while 重複輸入
	}
}