program main
  implicit none
  integer :: i, n, k
  character(10) :: s
  character(1) :: tar

  read *, n
  read *, s
  read *, k
  tar = s(k:k)

  do i = 1, n
    if (s(i:i) /= tar) then
      s(i:i) = '*'
    end if
  end do

  print '(a)', s

end program