var f:text;
    n,p,q,nr:longint;
    ok:boolean;
begin
assign(f,'fractii.in');
reset(f);
read(f,n);
close(f);
nr:=0;
for p:=1 to n do
    nr:=nr+1;
for p:=2 to n do
    for q:=1 to n do  begin
        ok:=false;
        if (p mod q<>0)or(q=1) then begin
           inc(nr);
           ok:=true;
           end;
        if ok and(q mod p=0)and(q<>1) then
           dec(nr);
        end;
assign(f,'fractii.out');
rewrite(f);
write(f,nr);
close(f);
end.