var
  a, b : char;
  i, k : integer;
  s : string;
begin
  readln(a);
  readln(b);
  readln(s);
  for i:=1 to length(s) do begin
    if (s[i]=a) and (k<>2) then begin
      write(b);
      k:=k+1;
    end
    else
      write(s[i]);
  end;
end.