Isn't it straightforward? Or are you looking for non-bruteforce methods. I don't know of a way if so.
Is a nice one-liner in most languages otherwise.
Edit: Guess you are wondering how to store such a large number? Using modulo (10) can help in that case. You need to understand a bit more of multiplication. Else just use BigNum/Etc
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Harsh J
www.harshj.com
Last edited by QwertyManiac; 30-07-2008 at 08:11 PM.