program fractr;
var p:array[1..1000000] of boolean;
    n,i,j,max,min:longint;
    s:qword;

function cmmdc(a,b:longint):longint;
begin
if a mod b=0 then cmmdc:=b
             else cmmdc:=cmmdc(b,a mod b);
end;

procedure ciur(n:longint);
var i,j:longint;
begin
p[2]:=true;
for i:=2 to n div 2 do
        begin
        j:=i+i;
        while j<=n do begin p[j]:=true; j:=j+i end;
        end;
end;

begin
assign(input,'fractii.in'); reset(input);
assign(output,'fractii.out'); rewrite(output);
read(n);
close(input);
ciur(n);
s:=n+n-1;
for i:=2 to n do
        for j:=2 to n do
                if j mod i<>0 then
                        if (not p[i])and(not p[j]) then s:=s+1
                                                  else begin
                                                  if i>j then begin max:=i; min:=j end
                                                         else begin max:=j; min:=i end;
                                                  if cmmdc(max,min)=1 then s:=s+1;
                                                        end;

write(s);
close(output);
end.