var a:array[1..100000000] of qword;
           i,j,k,n:qword;
                 fi,fo:text;
begin assign(fi,'fractii.in'); reset(fi);
      assign(fo,'fractii.out'); rewrite(fo);
      readln(fi,n);
      close(fi);
      i:=1;
      while i<=n do begin
                       a[i]:=i-1;
                       inc(i);
                     end;
      i:=2;
      while i<=n do begin
                      j:=i*2;
                      while j<=n do begin
                                      a[j]:=a[j]-a[i];
                                      inc(j,i);
                                     end;
                      inc(i);
                     end;
      i:=1;
      while i<=n do begin
                        k:=k+a[i];
                        inc(i);
                     end;
      k:=k+a[i];
      k:=k*2+1;
      writeln(fo,k);
      close(fo);
end.