3.txt

pl0

const true=1,false=0;
var x,y,m,n,pf;
procedure prime;
var i,f;
  procedure mod;
     x:=x-x/y*y;
begin  f:=true;
   i:=3;
   while i<m do
     begin x:=m;
       y:=i;
       call mod;
       if x=0 then f:=false;
       i:=i+2
     end;
   if f=true then
      begin
        write(m);
        pf:= true
      end
end;
begin
   pf:=false;
   read(n);
   while n>=2 do
   begin
      write(2);
      if n=2 then pf:=true;
      m:=3;
      while m<=n do
         begin call prime;
            m:=m+2
         end;
      read(n)
   end;
   if pf=false then write(0)
end.