program golf
  implicit none
  integer :: k, x, y, s, m, i, sx = 1, sy = 1, ix = 1, iy = 2
  integer :: v(1000000,2) = 0, r, d
  read(*,*) k
  read(*,*) x, y
  if (x < 0) then
    x = -x
    sx = -1
  end if
  if (y < 0) then
    y = -y
    sy = -1
  end if
  s = x+y
  if (mod(s,2) == 1 .and. mod(k,2) == 0) then
    write(*,'(i0)') -1
    stop
  end if
  if (s == k) then
    write(*,'(i0)') 1
    write(*,'(i0,x,i0)') sx*x, sy*y
    stop
  end if
  if (x < y) then
    m = x
    x = y
    y = m
    ix = 2
    iy = 1
  end if
  m = (s+k-1)/k
  if (m < 2) m = 2
  if (mod(s,2) /= mod(m*k,2)) m = m+1
  if (m == 3 .and. x < k) then
    v(1,:) = (/ x, -(k-x) /)
    v(2,:) = (/ x+(k+x-y)/2, -(k-x)+(k-x+y)/2 /)
    v(3,:) = (/ x, y /)
  else
    r = (m*k-s)/2
    do i = 1, m
      d = i*k
      if (d <= y+r) then
        v(i,:) = (/ 0, d /)
      else if (d <= y+r+x) then
        v(i,:) = (/ d-y-r, y+r /)
      else
        v(i,:) = (/ x, y+(m-i)*k /)
      end if
    end do
  end if
  write(*,'(i0)') m
  do i = 1, m
    write(*,'(i0,x,i0)') sx*v(i,ix), sy*v(i,iy)
  end do
  stop
end program golf