Program cel;
var f,g:text;
    n,nr,a,b:longint;

function cmmdc(x,y:integer):integer;
Begin
If x mod y=0 then cmmdc:=y
             else cmmdc:=cmmdc(y,x mod y);
end;

Begin
Assign(f,'fractii.in');Reset(f);
Assign(g,'fractii.out');Rewrite(g);
Read(f,n);
nr:=1;
a:=1;
nr:=0;
While a<=n do
 Begin
  b:=2;
  inc(nr);
  While (b<=n) do
   Begin
    If cmmdc(a,b)=1 then inc(nr);
    inc(b);
   end;
  inc(a);
 end;
Write(g,nr);
Close(f);
Close(g);
end.