print """
Welcome to the ISBN checker,
 
To use this program you will enter a 10 digit number to be converted to an International Standard Book Number
 
"""
 
ISBNNo = raw_input("please enter a ten digit number of choice") 
 
assert len(ISBNNo) == 10
 
counter = 11 #Set the counter to 11 as we multiply by 11 first
acc = 0 #Set the accumulator to 0
 
for i in ISBNNo[0:9]:
    print str(i) + " * " + str(counter)
    acc = acc + (int(i) * counter) #cast value a integer and multiply by counter
    counter -= 1 #decrement counter
print "Total = " + str(acc)                   
 
# Mod by 11 (divide and take remainder
 
acc = acc % 11
print "Mod by 11 = " + str(acc)
 
# take it from 11
 
acc = 11 - acc
print "subtract the remainder from 9 = " + str(acc)
 
# concatenate with string
 
ISBNNo = ISBNNo + (str(acc) if acc < 10 else 'X')
print "ISBN Number including check digit is: " + ISBNNo

cHJpbnQgIiIiCldlbGNvbWUgdG8gdGhlIElTQk4gY2hlY2tlciwKClRvIHVzZSB0aGlzIHByb2dyYW0geW91IHdpbGwgZW50ZXIgYSAxMCBkaWdpdCBudW1iZXIgdG8gYmUgY29udmVydGVkIHRvIGFuIEludGVybmF0aW9uYWwgU3RhbmRhcmQgQm9vayBOdW1iZXIKCiIiIgoKSVNCTk5vID0gcmF3X2lucHV0KCJwbGVhc2UgZW50ZXIgYSB0ZW4gZGlnaXQgbnVtYmVyIG9mIGNob2ljZSIpIAoKYXNzZXJ0IGxlbihJU0JOTm8pID09IDEwCgpjb3VudGVyID0gMTEgI1NldCB0aGUgY291bnRlciB0byAxMSBhcyB3ZSBtdWx0aXBseSBieSAxMSBmaXJzdAphY2MgPSAwICNTZXQgdGhlIGFjY3VtdWxhdG9yIHRvIDAKCmZvciBpIGluIElTQk5Ob1swOjldOgogICAgcHJpbnQgc3RyKGkpICsgIiAqICIgKyBzdHIoY291bnRlcikKICAgIGFjYyA9IGFjYyArIChpbnQoaSkgKiBjb3VudGVyKSAjY2FzdCB2YWx1ZSBhIGludGVnZXIgYW5kIG11bHRpcGx5IGJ5IGNvdW50ZXIKICAgIGNvdW50ZXIgLT0gMSAjZGVjcmVtZW50IGNvdW50ZXIKcHJpbnQgIlRvdGFsID0gIiArIHN0cihhY2MpICAgICAgICAgICAgICAgICAgIAoKIyBNb2QgYnkgMTEgKGRpdmlkZSBhbmQgdGFrZSByZW1haW5kZXIKCmFjYyA9IGFjYyAlIDExCnByaW50ICJNb2QgYnkgMTEgPSAiICsgc3RyKGFjYykKCiMgdGFrZSBpdCBmcm9tIDExCgphY2MgPSAxMSAtIGFjYwpwcmludCAic3VidHJhY3QgdGhlIHJlbWFpbmRlciBmcm9tIDkgPSAiICsgc3RyKGFjYykKCiMgY29uY2F0ZW5hdGUgd2l0aCBzdHJpbmcKCklTQk5ObyA9IElTQk5ObyArIChzdHIoYWNjKSBpZiBhY2MgPCAxMCBlbHNlICdYJykKcHJpbnQgIklTQk4gTnVtYmVyIGluY2x1ZGluZyBjaGVjayBkaWdpdCBpczogIiArIElTQk5Obw==

MDMwNjQwNjE1Mg==

0306406152