var i,j,c,n:longint;
    f,t:text;
Function diviz(a,b:integer):boolean;
var i:integer;
begin
  diviz:=true;
  if a>b then
  for i:=2 to a do
    if (a mod i = 0) and (b mod i = 0) then begin diviz:=false; exit; end;
  if b>a then
  for i:=2 to b do
    if (a mod i = 0) and (b mod i = 0) then begin diviz:=false; exit; end;  
end;
    
begin
 assign(f,'fractii.in');
   reset(f);
  read(f,n);
  c:=1;
   for i:=1 to n do
     for j:=1 to n do
       if (i<>j) and (diviz(i,j)=true) then writeln(i,'/',j) {inc(c)};
  assign(t,'fractii.out');
    rewrite(t);
      write(t,c);
 close(t);     
   
end.