My solution in pseudo code:

res:=0;
for k:=2 to 23 (every k is prime) do
 a:=amount of numbers i (2<=i<=S),that i%k==0;
 b:=amount of numbers i (2<=i<=S), that i%n==0 , where n - any prime
less than k
 if (a>=K)
 res+=Combinations(a,K);
 if (b>=K)
 res-=Combinations(b,K);
 if (res>=10000) then ...
end

write(res) ...

WA, and I dont know why. My prog gives right answer on tests written
here and in sample input, but WA.

Help, please