var v:array[1..1000003]of int64;
i,j,n:longint;
nr:int64;
begin
assign(input,'fractii.in'); reset(input);
assign(output,'fractii.out'); rewrite(output);
read(n);
for i:=1 to n do v[i]:=i-1;
for i:=2 to n do begin
    j:=2*i;
    while j<=n do begin
    v[j]:=v[j]-v[i];
    j:=j+i;
    end;
end;
nr:=0;
for i:=2 to n do nr:=nr+v[i];
write(2*nr+1);
close(output);
end.