function xor (id, pr, n, a):
  i := id
  part_xor := 0

  while i < n:
    part_xor ^= a[i]
    i += pr 

  send(0, part_xor)

  if id == 0:
    res := 0
    for i := 0 until pr:
      cur := receive(i)
      res ^= cur

    print(res)