Though I think my program is correct, the judger always give me WA,
why?
  Here is my code. I use a longint to save 4 digits:

program U1036;
const
  digits=10000;
type
  bignum=array[1..80] of longint;
var
  f:array[1..2,0..1000] of bignum;
  n,s,i,j,k,l:longint;
  re:array[1..400] of longint;
  ns:string;

  procedure add(p,q:longint);
  var
    i,j:longint;
  begin
    for i:=1 to 80 do begin
      inc(f[2,p,i],f[1,q,i]);
      if f[2,p,i]>digits then begin
        inc(f[2,p,i+1]);
        dec(f[2,p,i],digits);
      end;
    end;
  end;

begin
  readln(n,s);
  if n=0 then begin
    writeln(0);
    halt;
  end;
  fillchar(f,sizeof(F),0);
  for i:=0 to 9 do f[1,i,1]:=1;
  if (n*9*2<s)or odd(s) then begin
    writeln(0);
    halt;
  end;
  s:=s div 2;
  fillchar(f[2],sizeof(f[2]),0);
  for i:=2 to n do begin
    if 9*i>s then l:=s else l:=9*i;
    for j:=0 to 9*i do
      for k:=0 to 9 do
        add(j+k,j);
    if i<>n then begin
      f[1]:=f[2];
      fillchar(f[2],sizeof(f[2]),0);
    end;
  end;
  fillchar(re,sizeof(re),0);
  for i:=1 to 80 do
    for j:=1 to 80 do
      inc(re[i+j-1],f[2,s,i]*f[2,s,j]);
  for i:=1 to 400 do
    if re[i]>digits then begin
      inc(re[i+1],re[i] div digits);
      re[i]:=re[i] mod digits;
    end;
  i:=400;
  while (re[i]=0)and(i>0) do dec(i);
  if i=0 then writeln(0) else begin
    write(re[i]);
    for j:=i-1 downto 1 do begin
      str(re[j],ns);
      while length(ns)<4 do ns:='0'+ns;
      write(ns);
    end;
    writeln;
  end;
end.