var i,j,sum,n:longint;
    a:array[1..1000010] of longint;
    f,g:text;
procedure citire;
begin
assign(f,'fractii.in'); reset(f);
assign(g,'fractii.out'); rewrite(g);
readln(f,n);
end;
begin
citire;
sum:=0;
for i:=1 to n do
a[i]:=i-1;
for i:=2 to n do
begin
j:=2*i;
 while j<=n do
 begin
 a[j]:=a[j]-a[i];
 j:=j+i;
 end;
end;
for i:=1 to n do
sum:=sum+a[i];
sum:=(sum*2)+1;
writeln(g,sum);
close(g);
end.