

How for hell do Ukrainian train numbers work ?
I figured out how to know whether a train is a local, mainline, fast or Intercity train.
What I did not figure out :
The UZ app e.g. shows the train Odesa - Przemyśl as 036Ш. The opposite direction as 036Л.
The UZ online schedule shows the same train as 035 and 036.
The European schedule data in opposite shows the directions swapped with Odesa - Przemyśl as D 36 and the opposite direction D 35.
What's correct ? What do the letters mean ? I usually know Ш as fast train, Л on a ticket as two-seater class bur what does it mean in the train number ?