program fractii;

var
  n, i, f, j, a, b, temp,s,num,z: longint;
  in_f, out_f: text;
  v:array[1..1000000] of integer;
t:array[1..1000] of boolean;
ok:boolean;
begin
  assign(in_f, 'fractii.in');
  assign(out_f, 'fractii.out');
  reset(in_f);
 
  readln(in_f, n);

for i:=2 to n do t[i]:=true;  {se creeaza un tablou cu elemente de tip boolean}
for i:=2 to n do
  if t[i]=true then
    for j:=2 to n div i do
      t[i*j] := false;
      
     
     for i:=1 to n do
     begin  
     
       for j:=1 to n do
         begin
           ok:=true;
                if ((i=1) or ((j=1) and (i=1))) then 
                     begin
           writeln(i);
           writeln(j);
           writeln;
           inc(num);
         
           end else
             begin
           for z:=1 to i do
             
             if((t[z]=true )) then
         
      if (i mod z=0)then
     if(j mod z=0) then
       begin
          ok := false;
         break;
         end;
         
           if(ok) then
            begin
             writeln(i);
           writeln(j);
           writeln;
           inc(num);
           end;
       end;
       end;
end;
   rewrite(out_f);
  write(out_f, num);
  close(out_f);
  
end.