var
  n:int64;
  now:longint;
  f:array[0..200]of longint;

begin
  assign(input,'xcoins.in'); reset(input);
  assign(output,'xcoins.out'); rewrite(output);
  readln(n);
  f[5]:=1;
  f[6]:=6;
  f[7]:=3;
  f[8]:=4;
  f[9]:=3;
  f[10]:=2;
  f[11]:=3;
  f[12]:=4;
  f[13]:=3;
  f[14]:=4;
  f[15]:=3;
  f[16]:=4;
  f[17]:=5;
  f[18]:=4;
  f[19]:=5;
  f[20]:=4;
  if n<=20 then writeln(f[n])
  else begin
    if odd(n mod 5) then now:=1
    else now:=2;
    writeln(now+n div 5)
  end;
  close(input);
  close(output);
end.