//prime numbers
//a number is prime if it has no divisors amongst its smaller primes
//let's use this recursively!

declare a;
*print("yield prime number till");
*a=*gets();



function canbedividedbynoneofthese()
//the first argument is tested against all following
//returns true if not dividable by any
  {
  declare notdiv=1;
  declare u=1;
  while(*u<*#)
    {
    //following check is to avoid division by void arguments
    //to avoid BUG of the result() command, by which functions
    //do issue at least a single void result
    if(**u)
      {
      if(!(*0%(**u)))*notdiv=0;
      }
    *u=*u+1;
    }
  result(*notdiv);
  }


function allsmallerprimenumbersof(1)
//returns all prime numbers that are smaller than the argument
  {
  declare a=2,b;
//*print(allsmallerprimenumbersof,*0);
  while(*a<*0)
    {
    //*b=*sqrt(*a);  //attention! squares of primes as 25 will pass 
    *b=*sqrt(*a+1);
    if(*canbedividedbynoneofthese(*a,*allsmallerprimenumbersof(*b)))
      result(*a);
    *a=*a+1;
    }
  };

//note: there is no such thing as a main() call


*print(*allsmallerprimenumbersof(*a));