program frac;
var f:text;
    n,i,s,j:longint;
function prim(a,b:longint):boolean;
 var r:longint;
 begin
   repeat
   r:=a mod b;
   a:=b;
   b:=r;
  until r=0;
  if a=1 then
   prim:=true
  else
   prim:=false;
 end;
begin
 assign(f,'fractii.in');
 reset(f);
 read(f,n);
 close(f);
 s:=2*n-1;
 for i:=2 to n do
  for j:=i+1 to n do
   if j=i+1 then
    s:=s+2
   else
    if prim(i,j)=true then
     s:=s+2;
 assign(f,'fractii.out');
 rewrite(f);
 write(f,s);
 close(f);
 end.