program fractii_4;
var i,n,j:longint;
s:int64;
a:array [1..1000000] of longint;
begin
assign(input,'fractii.in');reset(input);
assign(output,'fractii.out');rewrite(output);
read(n);
for i:=1 to n do
a[i]:=i-1;
for i:=2 to (n div 2)+1 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
s:=s+a[i];
write(2*s+1);
end.