/* REXX   Checks the key numbers for Marienbad.
*/
x.    =
x.1   = '1'x
x.2   = '2'x
x.3   = '3'x
x.4   = '4'x
x.5   = '5'x
x.6   = '6'x
x.7   = '7'x
"NEWSTACK"
do forever
   pull a b c d .
   if a = "" then leave
   say c2x(BitXOR(BitXOR(BitXOR(x.a,x.b),x.c),x.d))
end
"DELSTACK"
exit