var
  d1,d2 : longint;
  s1 : string;
  c1,c2 : char;
begin
  readln(c1);
  readln(c2);
  readln(s1);
  d1:=pos(s1,c1);
  s1[d1]:=c2;
  d2:=pos(s1,c1);
  s1[d2]:=c2;
  writeln(s1);
end.