program p1;
var a,b,n,i,j,nr:integer;
f,g:text;
v:array[1..200000] of longint;
begin
assign(f,'fractii.in');reset(f);
assign(g,'fractii.out');rewrite(g);
read(f,n);
nr:=0;
For i:=1 to n do begin
v[i]:=i-1;
end;
For i:=2 to n do
For j:=2 to n-1 do
v[i*j]:=v[i*j]-v[i];
nr:=1;
For i:= 1 to n do
nr:=nr+2*v[i];
write(g,nr);
close(f);
close(g);
end.