program main
 implicit none

 integer N,K,i
 character*80 S,e
 read(*,*) N,S,K
 e(1:1) = S(K:K)
 do i=1,N
  if(S(i:i) /= e(1:1)) then
   S(i:i) = '*'
  end if
 end do

 write(*,*) S   
end program main