program main
  implicit none
  integer(8) N, nd, ns, i, firsts, nd2,ans, finald, ns2
  !integer loc(4) loc2(4) !left ., left #, right ., right #
  character(2*(10**5)) S
  read(*, *) N
  read(*, *) S
  nd = 0
  !ns = 0
  firsts = N
  finald = 1
  ns2 = 0
  nd2 = 0
  do i = 1,N
    if (S(i:i) == '.') then
      nd = nd + 1
    else
      ns = ns + 1
    end if
  end do
  !if (ns /= 0) then


      do i = firsts,N
        if (S(i:i) == '.') then
          nd2 = nd2 + 1
        end if
      end do

  !end if
  !if (nd /= 0) then
    do i = 1,N
      if (S(i:i) == '.') then
        finald = i
      end if
    end do
      do i = 1,finald
        if (S(i:i) == '#') then
          ns2 = ns2 + 1
        end if
      end do

  
  ans = min(nd, nd2, ns2)
  write(*,'(i0)') ans
end program main
