type vector=array[1..100]of integer;
var n,i,j,s:longint;f1,f2:text;v:vector;
Function ired(x,y:integer;v:vector):integer;
var z,m:integer;
label 1;
begin
If x>y then z:=y
else z:=x;
ired:=0;m:=0;
Repeat m:=m+1;
If (x mod v[m]=0)and(y mod v[m]=0)then begin
ired:=1;
goto 1;
end;
until v[m]>=z;
1:End;
begin
assign(f1,'fractii.in');reset(f1);
assign(f2,'fractii.out');rewrite(f2);
read(f1,n);
s:=1;
v[1]:=2;
v[2]:=3;
v[3]:=5;
v[4]:=7;
v[5]:=11;
v[6]:=13;
v[7]:=17;
v[8]:=19;
v[9]:=23;
v[10]:=29;
v[11]:=31;
v[12]:=37;
v[13]:=39;
v[14]:=41;
v[15]:=43;
v[16]:=47;
v[17]:=51;
v[18]:=53;
v[19]:=59;
v[20]:=61;
For i:=1 to n-1 do begin
For j:=i+1 to n do begin
If ired(i,j,v)=0 then s:=s+2;
end;
end;
write(f2,s);
close(f1);
close(f2);
end.