改成递推就行了
var
  f:array[1..30,0..30] of longint;
  m,n,i,j,t:integer;
begin
  readln(m,n);
  t:=0;
  while (m+n<>0) do
    begin
      inc(t);
      fillchar(f,sizeof(f),0);
      for i:=1 to m do f[i,0]:=i;
      for i:=0 to n do f[1,i]:=1;
      for i:=1 to m do
        for j:=1 to n do f[i,j]:=f[i-1,j-1]+f[i-1,j]+1;
      writeln('Case ',t,': ',f[m,n]);
      readln(m,n);
    end;
end.