program main
  implicit none
  integer::N,i
  integer*8,allocatable::course(:,:)

  read *,N
  allocate(course(1:3,1:N))

  course(1,1) = 1 !ken
  course(2,1) = 0 !kenken
  course(3,1) = 0 !pa
  do i=2,N
     course(1,i) = course(3,i-1)
     course(2,i) = course(1,i-1)
     course(3,i) = MOD(course(1,i-1) + course(2,i-1), 10**9+7)
  end do
  print '(i0)',MOD(SUM(course(1:3,N)),10**9+7)

end program main