program coins;
var
  a:array[5..16]of longint;
  n,i:int64;
begin
  assign(input,'xcoins.in');
  reset(input);
  assign(output,'xcoins.out');
  rewrite(output); 


  a[5]:=1;
  a[6]:=6;
  a[7]:=3;
  a[8]:=4;
  a[9]:=3;
  a[10]:=2;
  a[11]:=3;
  a[12]:=4;
  a[13]:=3;
  a[14]:=4;
  a[15]:=3;

  readln(n);
  if n<=15 then writeln(a[n])
  else
  begin

    i:=n div 5-2;
    i:=i+a[(n mod 5)+10];

    writeln(i);
  end;

  close(input);
  close(output);
end.