program mainb
  implicit none
  integer(8)::n,i
  real(8),allocatable::a(:)
  real(8)::ans

   read*,n
   allocate(a(n))

  read*,a
  !print*,a


  ans=1
  do i=1,n
   ans=a(i)*ans
   !print*,ans
   
  end do

if (ans/100.0>10000000000000000.0) then
     ans=-1
   end if
  
200 print*,ans

end program mainb
