program text;
var t1,t2:text; i:integer;
a: array [1..500] of string;
begin
assign (t1,'text.in');
assign (t2,'text.out');
begin
assign (t1,'text.in');
assign (t2,'text.out');
reset (t1);
read (t1,a[i]);
begin
if a=A then a:=A;
ifr b=B then b:=B;