var f:text;
    n,j,i,s,r:longint;
    ok:boolean;
    begin
assign(f, 'fractii.in');
reset(f);
read(f,n);
s:=n;
close(f);
for i:=2 to n do
begin
j:=2;
s:=s+1;
 while j<=n do
  begin
  ok:=true;
   r:=2;
    while r<=i do
   begin
    if i mod r=0 then
     if (j mod r=0) or (r mod j=0) then
       begin
       ok:=false;
       r:=100000000;
       end;
   r:=r+1;
   end;
    if ok=true then
     s:=s+1;
    j:=j+1;
  end;
end;
assign(f, 'fractii.out');
rewrite(f);
write(f,s);
close(f);
end.