ISBN2 by notogawa

m@main=getLine>>=putStrLn.h>>m
h s=[t|t<-f s,let n=mod(length t)2,1>mod(sum[sum[a|x<-w,x<b]|(a,b)<-zip([[10,9..],cycle[1,3]]!!n)$drop 4t])(11-n)]!!0
f('?':s)=map(:s)w
f(a:s)=map(a:)$f s
w=['0'..'9']

Note that non-ascii characters in the above source code will be escaped (such as \x9f).

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