program fractii;
   var  n,q,i,l,d,r,p:longint;f,g:text;
   begin
   assign(f,'fractii.in');reset(f);
   assign(g,'fractii.out');rewrite(g);
   readln(f,n);p:=1;
   repeat
   inc(q);
   if p>q then begin d:=p;i:=q; end else begin d:=q;i:=p;end;
   r:=d mod i;
   while r<>0 do begin
   d:=i;
   i:=r;
   r:=d mod i;end;
   if i=1 then inc(l);if q=n then begin inc(p);q:=0;end;
   until p=n+1;
   write(g,l);
   close(f);
   close(g);
   end.