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.