Ehrenfest's urn

[zahi48g]

Thank you D Lachieze and John Keith.

I've learned two things : How to remove properly an object from a list

and that L1(0) refers to the last element of list L1 (am I right ?) .

But i've got one question for D Lachieze . In order to know if n belongs to L1, shouldn't you write

" IF POS(L1,n)>0 THEN ..." instead of " IF POS(L1,n) THEN ..." ?

Thank you