program fractii;
type vect = array[1..100,1..100] of boolean;
var A : vect;
    m,n,i,j,l,S : longint;
    f : text;
function max(x,y:longint):longint;
begin
max := (x+y+abs(x-y)) div 2;
end;

begin
assign(f,'fractii.in');
reset(f);
read(f,n);
close(f);

for i := 1 to n do
for j := 1 to n do
A[i,j] := true;

for i := 1 to n do
for j := 1 to n do
if A[i,j] then
          for l := 2 to n div max(i,j) do  A[i*l,j*l] := false;

S :=0;

for i := 1 to n do
for j := 1 to n do
if A[i,j] then S := S+1;

assign(f,'fractii.out');
rewrite(f);
write(f,S);
close(f);
end.