program z3;

{$APPTYPE CONSOLE}

var f1,f2:text;
    a,b,n,i,j,k:longint;

begin
assign(f1,'pair.in');
assign(f2,'pair.out');
reset(f1);
readln(f1,n);
close(f1);
rewrite(f2);
k:=0;
for i:=1 to n do
begin
k:=k+n div i;
end;
writeln(f2,k);
close(f2);
end.