PROGRAM ATCODER

implicit none
integer :: n,k,i
character(len=10) :: s
character(len=1) :: c

read*, n,s,k

c = s(k:k)

do i = 1, len_trim(s)
  if ( s(i:i) /= c ) then
    s(i:i) = '*'
  end if
end do

print'(a)', trim(s) 

END PROGRAM ATCODER