// permutation generation

// N = 4
N, val[4], id

writeperm()
  i = 0
  while( i<N )
    print(val[i], " ")
    i = i + 1
  print("\n")

visit(k)
  id = id + 1
  val[k] = id
  if( id == N - 1) writeperm()
  t = 0
  while( t<N )
    if( val[t] == 0 ) visit(t)
    t = t + 1
  id = id - 1
  val[k] = 0

main()
  N = 4
  i = 0
  while( i<N )
    val[i] = 0
    i = i + 1
  id = 0 -1
  visit(0)

