var n,i,j,s:integer;h,g:text;
function f(a,b:integer):integer;
var r:integer;
begin
while r<>0 do begin
r:=a mod b;
a:=b;
b:=r;
end;
f:=a;
end;
begin
assign(h,'fractii.in');reset(h);
assign(g,'fractii.out');rewrite(g);
read(h,n);
for i:=2 to n do
for j:=1 to i-1 do
if (i mod 2=1) and(j mod 2=1) then
if f(i,j)=1 then s:=s+1;
s:=s*2+1;
write(g,s);
close(g);
close(h);
readln;
end.