var f,g:text;
a:array[1..100] of boolean;
i,j,k,l,m,n,s:longint;
function t(N:longint):longint;
var i:longint;
r:real;
begin
r:=n;
for i:=2 to n do
    if (a[i]=true) and (n mod i=0) then
                              r:=r*(1-1/i);
t:=trunc(R);
end;
begin
assign(f,'fractii.in');
assign(g,'fractii.out');
reset(F);
rewrite(G);readln(f,n);
for i:=2 to n do
    a[i]:=true;
for i:=2 to n do
    if a[i]=true then
                 begin
                 j:=i;
                 repeat
                 j:=j+i;
                 a[j]:=false;
                 until j+i>n;
                 end;
for i:=2 to n do
            s:=s+t(I);
writeln(g,s);close(F);close(G);
end.