Arithmetic $begingroup$ I do think I disagree with Kelvin Soh a bit, in that he appears to allow for a route to repeat the same vertex, and I believe this is simply not a typical definition. I might say: Kelvin SohKelvin Soh one,8151212 silver badges1515 bronze badges $endgroup$ one two https://andyf051eef8.losblogos.com/profile