var p,q,n,i,j,nr,aux,aux1:longint;
    g,h:text;
begin
assign(g,'fractii.in');
reset(g);
read(g,n);
close(g);
for i:=1 to n do  begin
p:=p+1;
for j:=1 to n do begin
if q=n then q:=0;
q:=q+1;
aux:=p;
aux1:=q;
while (aux>0)and (aux1>0) do
if aux>aux1 then aux:=aux-aux1
       else aux1:=aux1-aux;
if (aux1=1) or (aux=1) then nr:=nr+1;
end;
if i=n then break;
end;
assign(h,'fractii.out');
rewrite(h);
write(h,nr);
close(h);
end.