var f,g:text;
    n,i,j,a,b,k,c:longint;

function cmmdc(i,j:longint):longint;
begin
a:=i;
b:=j;
 while a<>b do
                         begin
                         if a>b then a:=a-b;
                         if b>a then b:=b-a;
                         end;
 cmmdc:=a;
 end;
begin
assign(f,'fractii.in');reset(f);
assign(g,'fractii.out');rewrite(g);
readln(f,n);
repeat
inc(i);
for j:=1 to n do
              begin
              c:=cmmdc(i,j);
              if c=1 then inc(k);
              end;
until i=n;
writeln(g,k);
close(f);
close(g);
end.