Is it a dynamic problem?
I think it is.
But i got W.A. again and again.
Who can help me?
I think when N=50 S=450 , the answer is largest.
So who can tell me the answer to N=50 S=450?
And is there any other testdata which will cause me
wrong more probably?
Thanks.

I am from Hangzhou foreign language school, now study in
Zhe Jiang province, and preparing for acm regional in
shanghai, contact me, oicq:7231952, email:tjq@hfls.net

This problem  can be solved by Dynamic Programming method clearly.
when N = 50 S = 450 the answer is too large but I think there's a guarantee that the answer can be stored in a 32-bit integer variable.
I 've got ACCEPTED with a solution used 32-bit integer.

> Is it a dynamic problem?
> I think it is.
> But i got W.A. again and again.
> Who can help me?
> I think when N=50 S=450 , the answer is largest.
> So who can tell me the answer to N=50 S=450?
> And is there any other testdata which will cause me
> wrong more probably?
> Thanks.
>

OK!
My Oicq: 452854
I am also going to ACM in shanghai.
See you there.

> I am from Hangzhou foreign language school, now study in
> Zhe Jiang province, and preparing for acm regional in
> shanghai, contact me, oicq:7231952, email:tjq@hfls.net

Then what is the answer to N=20 S=180?
I got the answer is 9498224252518411749770217561201985600.
My god. Do u think it is too large?

Hey , it isn't what I mention , I said that the correct answer according to the judge input can be stored in 32-bit integer variable.
Hmm , i think your answer to N = 20 S =180 is correct.
Some answers to big N and S :   ( have you got them too ?? )
20  20   : 401200499400100
20  180 : 9498224252518411749770217561201985600
30  100 : 6973685507344299790997740051842388725207204
40  200 : 86216101043642784690721376717552539070315729868258187643854533478596
50 320  : 124507115377465723047808268606085575853100575373485121453662425175753835145673415371788929600
50 450  : 3834688188199309756675466732967588185862422492337212276545580039517258085033387305291001857619600


> Then what is the answer to N=20 S=180?
> I got the answer is 9498224252518411749770217561201985600.
> My god. Do u think it is too large?
>

Every answer you give me is all right!
So i think there is maybe some tricky testdata.

Hmm , maybe you forget to print 0 when S is odd.

> Every answer you give me is all right!
> So i think there is maybe some tricky testdata.
>

I have noticed that already.
:(
My god!
What happened to my program?
Bad luck!

So , what about the answer to some N and S = 0 ?

> I have noticed that already.
> :(
> My god!
> What happened to my program?
> Bad luck!
>

But in problem text, it says that N>0 !!!
And if n=0 i think the answer is 0.

Oh my god!
thank you very much!
i add a line as follows:
if n=0 then begin writeln(0); exit; end;

It passed!!!!!
My god!
Thank you!