program reactivi;
    type temp=record
               min,max:integer;
               end;
    var  n,i,j,k,min,max:integer;
         a:array[1..8000] of temp;
         c:temp;fi,fo:text;

begin
     assign(fi,'reactivi.in');reset(fi);
     assign(fo,'reactivi.out');rewrite(fo);
     readln(n);close(fi);
     for i:=1 to n do
                         read(a[i].min,a[i].max);
     for i:=1 to n-1 do
            for j:=1 to n do
                           begin
                                 if a[i].min>a[j].min then begin
                                                              c:=a[j];
                                                              a[j]:=a[i];
                                                              a[i]:=c;
                                                          end;
                             end;
     k:=1;min:=a[1].min;max:=a[1].max;
     for i:=2 to n do
            if a[i].min>max then begin
                                       inc(k);
                                       min:=a[i].min;
                                       max:=a[i].max;
                                  end
                           else
                               begin
                                     if (a[i].min>min) then min:=a[i].min;
                                     if (a[i].max<max) then max:=a[i].max;
                                  end;

      writeln(k);
      close(fo);

end.