program main

  implicit none

  integer :: n, a, b
  integer, allocatable :: sumi(:)
  integer    :: i

  integer(8)   :: ans

  read(*,*) n, a, b
  allocate( sumi(n) )
  
  ans = 1 
  sumi = 0
  do i = 1, n
    ans = ans * int( i, kind=8 )
    sumi(i) = ans
  end do
  
  ans = 0 
  do i = 1, n
    if( i == a .or. i == b ) cycle 
    if( i == n ) then
      ans = ans + 1
    else
      ans = ans + int( sumi(n)/sumi(i)/sumi(i) )
    end if
  end do

  print*, mod( ans, ( 10*9 + 7 ) )

end program main
