type tip=1..1000000;
var n,i,j:tip;
    f:text;
    nr:longint;
procedure citire;
begin
assign(f,'fractii.in');reset(f);
readln(f,n);
close(f);
end;

begin
citire;
nr:=n;
for i:=2 to n do
    for j:=1 to n do
        if j=1 then nr:=nr+1
        else if i mod j<>0 then nr:=nr+1;
assign(f,'fractii.out');rewrite(f);
writeln(f,nr-1);
close(f);
end.